Browsing by Author "Valenti, S."

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    450 d of Type II SN 2013ej in optical and near-infrared
    (OXFORD UNIV PRESS, 2016) Yuan, Fang; Jerkstrand, A.; Valenti, S.; Sollerman, J.; Seitenzahl, I. R.; Pastorello, A.; Schulze, S.; Chen, T. W.; Childress, M. J.; Fraser, M.; Fremling, C.; Kotak, R.; Ruiter, A. J.; Schmidt, B. P.; Smartt, S. J.; Taddia, F.; Terreran, G.; Tucker, B. E.; Barbarino, C.; Benetti, S.; Elias Rosa, N.; Gal Yam, A.; Howell, D. A.; Inserra, C.; Kankare, E.; Lee, M. Y.; Li, K. L.; Maguire, K.; Margheim, S.; Mehner, A.; Ochner, P.; Sullivan, M.; Tomasella, L.; Young, D. R.
    We present optical and near-infrared photometric and spectroscopic observations of SN 2013ej, in galaxy M74, from 1 to 450 d after the explosion. SN 2013ej is a hydrogen-rich supernova, classified as a Type IIL due to its relatively fast decline following the initial peak. It has a relatively high peak luminosity (absolute magnitude M-V =-17.6) but a small 56Ni production of similar to 0.023 M-circle dot. Its photospheric evolution is similar to other Type II SNe, with shallow absorption in the H a profile typical for a Type IIL. During transition to the radioactive decay tail at similar to 100 d, we find the SN to grow bluer in B - V colour, in contrast to some other Type II supernovae. At late times, the bolometric light curve declined faster than expected from Co-56 decay and we observed unusually broad and asymmetric nebular emission lines. Based on comparison of nebular emission lines most sensitive to the progenitor core mass, we find our observations are best matched to synthesized spectral models with a M-ZAMS = 12-15 M-circle dot progenitor. The derived mass range is similar to but not higher than the mass estimated for Type IIP progenitors. This is against the idea that Type IIL are from more massive stars. Observations are consistent with the SN having a progenitor with a relatively low-mass envelope.
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    Early observations of the nearby Type Ia supernova SN 2015F
    (2017) Cartier, R.; Sullivan, M.; Firth, R. E.; Pignata, G.; Mazzali, P.; Maguire, K.; Childress, M. J.; Arcavi, I.; Ashall, C.; Bassett, B.; Crawford, S. M.; Frohmaier, C.; Galbany, L.; Gal-Yam, A.; Hosseinzadeh, G.; Howell, D. A.; Inserra, C.; Johansson, J.; Kasai, E. K.; McCully, C.; Prajs, S.; Prentice, S.; Schulze, S.; Smartt, S. J.; Smith, K. W.; Smith, M.; Valenti, S.; Young, D. R.
    We present photometry and time series spectroscopy of the nearby Type Ia supernova (SN Ia) SN 2015F over -16 d to +80 d relative to maximum light, obtained as part of the Public ESO Spectroscopic Survey of Transient Objects. SN 2015F is a slightly sub-luminous SN Ia with a decline rate of Delta m15(B) = 1.35 +/- 0.03 mag, placing it in the region between normal and SN 1991bg-like events. Our densely sampled photometric data place tight constraints on the epoch of first light and form of the early-time light curve. The spectra exhibit photospheric C II lambda 6580 absorption until -4 days, and high-velocity Ca II is particularly strong at <-10 d at expansion velocities of 23 000 km s(-1). At early times, our spectral modelling with SYN++ shows strong evidence for iron-peak elements ( Fe (II), Cr (II), Ti (II), and V-II) expanding at velocities > 14 000 km s(-1), suggesting mixing in the outermost layers of the SN ejecta. Although unusual in SN Ia spectra, including VII in the modelling significantly improves the spectral fits. Intriguingly, we detect an absorption feature at similar to 6800 angstrom that persists until maximum light. Our favoured explanation for this line is photospheric Al II, which has never been claimed before in SNe Ia, although detached high-velocity CII material could also be responsible. In both cases, the absorbing material seems to be confined to a relatively narrow region in velocity space. The nucleosynthesis of detectable amounts of Al II would argue against a low-metallicity white dwarf progenitor. We also show that this 6800 feature is weakly present in other normal SN Ia events and common in the SN 1991bg-like sub-class.
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    Interacting supernovae and supernova impostors. LSQ13zm : an outburst heralds the death of a massive star
    (2016) Tartaglia, L.; Pastorello, A.; Sullivan, M.; Baltay, C.; Rabinowitz, D.; Nugent, P.; Drake, A. J.; Djorgovski, S. G.; Gal-Yam, A.; Bauer, Franz Erik; Barsukova, E. A.; Goranskij, V. P.; Valeev, A. F.; Fatkhullin, T.; Schulze, S.; Mehner, A.; Fabrika, S.; Taubenberger, S.; Nordin, J.; Valenti, S.
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    LSQ14bdq: A TYPE Ic SUPER-LUMINOUS SUPERNOVA WITH A DOUBLE-PEAKED LIGHT CURVE
    (2015) Nicholl, M.; Smartt, S. J.; Jerkstrand, A.; Sim, S. A.; Inserra, C.; Anderson, J. P.; Baltay, C.; Benetti, S.; Chambers, K.; Chen, T. -W.; Elias-Rosa, N.; Feindt, U.; Flewelling, H. A.; Fraser, M.; Gal-Yam, A.; Galbany, L.; Huber, M. E.; Kangas, T.; Kankare, E.; Kotak, R.; Kruehler, T.; Maguire, K.; McKinnon, R.; Rabinowitz, D.; Rostami, S.; Schulze, S.; Smith, K. W.; Sullivan, M.; Tonry, J. L.; Valenti, S.; Young, D. R.
    We present data for LSQ14bdq, a hydrogen-poor super-luminous supernova (SLSN) discovered by the La Silla QUEST survey and classified by the Public ESO Spectroscopic Survey of Transient Objects. The spectrum and light curve are very similar to slow-declining SLSNe such as PTF12dam. However, detections within similar to 1 day after explosion show a bright and relatively fast initial peak, lasting for similar to 15 days, prior to the usual slow rise to maximum light. The broader, main peak can be fit with either central engine or circumstellar interaction models. We discuss the implications of the precursor peak in the context of these models. It is too bright and narrow to be explained as a normal Ni-56-powered SN, and we suggest that interaction models may struggle to fit the two peaks simultaneously. We propose that the initial peak may arise from the post-shock cooling of extended stellar material, and reheating by a central engine drives the second peak. In this picture, we show that an explosion energy of similar to 2 X 10(52) erg and a progenitor radius of a few hundred solar radii would be required to power the early emission. The competing engine models involve rapidly spinning magnetars (neutron stars) or fallback onto a central black hole. The prompt energy required may favor the black hole scenario. The bright initial peak may be difficult to reconcile with a compact Wolf-Rayet star as a progenitor since the inferred energies and ejected masses become unphysical.
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    Massive stars exploding in a He-rich circumstellar medium - V. Observations of the slow-evolving SN Ibn OGLE-2012-SN-006
    (2015) Pastorello, A.; Wyrzykowski, L.; Valenti, S.; Prieto, J. L.; Kozlowski, S.; Udalski, A.; Elias-Rosa, N.; Morales-Garoffolo, A.; Anderson, J. P.; Benetti, S.; Bersten, M.; Botticella, M. T.; Cappellaro, E.; Fasano, G.; Fraser, M.; Gal-Yam, A.; Gillone, M.; Graham, M. L.; Greiner, J.; Hachinger, S.; Howell, D. A.; Inserra, C.; Parrent, J.; Rau, A.; Schulze, S.; Smartt, S. J.; Smith, K. W.; Turatto, M.; Yaron, O.; Young, D. R.; Kubiak, M.; Szymanski, M. K.; Pietrzynski, G.; Soszynski, I.; Ulaczyk, K.; Poleski, R.; Pietrukowicz, P.; Skowron, J.; Mroz, P.
    We present optical observations of the peculiar Type Ibn supernova (SN Ibn) OGLE-2012-SN-006, discovered and monitored by the Optical Gravitational Lensing Experiment-IV survey, and spectroscopically followed by Public ESO Spectroscopic Survey of Transient Objects (PESSTO) at late phases. Stringent pre-discovery limits constrain the explosion epoch with fair precision to JD = 245 6203.8 +/- 4.0. The rise time to the I-band light-curve maximum is about two weeks. The object reaches the peak absolute magnitude M-I = -19.65 +/- 0.19 on JD = 245 6218.1 +/- 1.8. After maximum, the light curve declines for about 25 d with a rate of 4 mag (100 d)(-1). The symmetric I-band peak resembles that of canonical Type Ib/c supernovae (SNe), whereas SNe Ibn usually exhibit asymmetric and narrower early-time light curves. Since 25 d past maximum, the light curve flattens with a decline rate slower than that of the Co-56-Fe-56 decay, although at very late phases it steepens to approach that rate. However, other observables suggest that the match with the Co-56 decay rate is a mere coincidence, and the radioactive decay is not the main mechanism powering the light curve of OGLE-2012-SN-006. An early-time spectrum is dominated by a blue continuum, with only a marginal evidence for the presence of He I lines marking this SN type. This spectrum shows broad absorptions bluewards than 5000 angstrom, likely O II lines, which are similar to spectral features observed in superluminous SNe at early epochs. The object has been spectroscopically monitored by PESSTO from 90 to 180 d after peak, and these spectra show the typical features observed in a number of SN 2006jc-like events, including a blue spectral energy distribution and prominent and narrow (v(FWHM) approximate to 1900 km s(-1)) He I emission lines. This suggests that the ejecta are interacting with He-rich circumstellar material. The detection of broad (10(4) km s(-1)) O I and Ca II features likely produced in the SN ejecta (including the [OI] lambda lambda 6300,6364 doublet in the latest spectra) lends support to the interpretation of OGLE-2012-SN-006 as a core-collapse event.
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    On the diversity of superluminous supernovae : ejected mass as the dominant factor
    (2015) Nicholl, M.; Smartt, S.; Jerkstrand, A.; Inserra, C.; Sim, S.; Chen, T.; Benetti, S.; Fraser, M.; Bauer, Franz Erik; Schulze, S; Maguire, K.; Smith, K.; Sullivan, M.; Valenti, S.; Young, D.; Gal-Yam, A.; Kankare, E.
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    On the nature of hydrogen-rich superluminous supernovae
    (2018) Inserra, C.; Smartt, S. J.; Gall, E. E. E.; Leloudas, G.; Chen, T-W.; Schulze, S.; Jerkstrand, A.; Nicholl, M.; Anderson, J. P.; Arcavi, I.; Benetti, S.; Cartier, R. A.; Childress, M.; Della Valle, M.; Flewelling, H.; Fraser, M.; Gal-Yam, A.; Gutierrez, C. P.; Hosseinzadeh, G.; Howell, D. A.; Huber, M.; Kankare, E.; Kruehler, T.; Magnier, E. A.; Maguire, K.; McCully, C.; Prajs, S.; Primak, N.; Scalzo, R.; Schmidt, B. P.; Smith, M.; Smith, K. W.; Tucker, B. E.; Valenti, S.; Wilman, M.; Young, D. R.; Yuan, F.
    We present two hydrogen-rich superluminous supernovae (SLSNe): SN2103hx and PS 15br. These objects, together with SN2008es, are the only SLSNe showing a distinct, broad H alpha feature during the photospheric phase; also, they show no sign of strong interaction between fast moving ejecta and circumstellar shells in their early spectra. Despite the fact that the peak luminosity of PS 15br is fainter than that of the other two objects, the spectrophotometric evolution is similar to SN2103hx and different from any other supernova in a similar luminosity space. We group all of them as SLSNe II and hence they are distinct from the known class of SLSN IIn. Both transients show a strong, multicomponent H alpha emission after 200 d past maximum, which we interpret as an indication of the interaction of the ejecta with an asymmetric, clumpy circumstellar material. The spectra and photometric evolution of the two objects are similar to Type II supernovae, although they have much higher luminosity and evolve on slower time-scales. This is qualitatively similar to how SLSNe I compare with normal type Ic, in that the former are brighter and evolve more slowly. We apply a magnetar and an interaction semi-analytical code to fit the light curves of our two objects and SN2008es. The overall observational data set would tend to favour the magnetar, or central engine, model as the source of the peak luminosity, although the clear signature of late-time interaction indicates that interaction can play a role in the luminosity evolution of SLSNe II at some phases.
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    PESSTO : survey description and products from the first data release by the Public ESO Spectroscopic Survey of Transient Objects
    (2015) Smartt, S. J.; Valenti, S.; Fraser, M.; Inserra, C.; Young, D. R.; Sullivan, M.; Bauer, Franz Erik; Clocchiatti, Alejandro; Romero Cañizales, Cristina; Schulze, S.; Pastorello, A.; Benetti, S.; Gal-Yam, A.; Knapic, C.; Molinaro, M.; Smareglia, R.; Smith, K. W.; Taubenberger, S.; Yaron, O.; Anderson, J. P.; Ashall, C.; Balland, C.; Baltay, C.; Barbarino, C.; Baumont, S.; Bersier, D.; Blagorodnova, N.; Bongard, S.; Botticella, M. T.; Bufano, F.; Bulla, M.; Cappellaro, E.; Campbell, H.; Cellier-Holzem, F.; Chen, T. W.; Childress, M. J.; Contreras, C.; Dall’Ora, M.; Danziger, J.; de Jaeger, T.; De Cia, A.; Della Valle, M.; Dennefeld, M.; Elias Rosa, N.; Elman, N.; Feindt, U.; Fleury, M.; Gall, E.; González Gaitan, S.; Galbany, L.; Morales Garoffolo, A.; Greggio, L.; Guillou, L. L.; Hachinger, S.; Hadjiyska, E.; Hage, P. E.; Hillebrandt, W.; Hodgkin, S.; Hsiao, E. Y.; James, P. A.; Jerkstrand, A.; Kangas, T.; Kankare, E.; Kotak, R.; Kromer, M.; Kuncarayakti, H.; Leloudas, G.; Lundqvist, P.; Lyman, J. D.; Hook, I. M.; Maguire, K.; Manulis, I.; Margheim, S. J.; Mattila, S.; Maund, J. R.; Mazzali, P. A.; McCrum, M.; McKinnon, R.; Moreno Raya, M. E.; Nicholl, M.; Nugent, P.; Pain, R.; Pignata, Giuliano; Phillips, M. M.; Polshaw, J.; Pumo, M. L.; Rabinowitz, D.; Reilly, E.; Scalzo, R.; Schmidt, B.; Sim, S.; Sollerman, J.; Taddia, F.; Tartaglia, L.; Terreran, G.; Tomasella, L.; Turatto, M.; Walker, E.; Walton, N. A.; Wyrzykowski, L.; Yuan, F.; Zampieri, L.
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    SN 2004aw
    (2006) Taubenberger, S.; Pastorello, A.; Mazzali, P. A.; Valenti, S.; Pignata, G.; Sauer, D. N.; Arbey, A.; Baernbantner, O.; Benetti, S.; Della Valle, A.; Deng, J.; Elias-Rosa, N.; Filippenko, A. V.; Foley, R. J.; Goobar, A.; Kotak, R.; Li, W.; Meikle, P.; Mendez, J.; Patat, F.; Pian, E.; Ries, C.; Ruiz-Lapuente, P.; Salvo, M.; Stanishev, V.; Turatto, M.; Hillebrandt, W.
    Optical and near-infrared (near-IR) observations of the Type Ic supernova (SN Ic) 2004aw are presented, obtained from -3 to +413 d with respect to the B-band maximum. The photometric evolution is characterized by a comparatively slow post-maximum decline of the light curves. The peaks in redder bands are significantly delayed relative to the bluer bands, the I-band maximum occurring 8.4 d later than that in B. With an absolute peak magnitude of -18.02 in the V band the SN can be considered fairly bright, but not exceptional. This also holds for the U through I bolometric light curve, where SN 2004aw has a position intermediate between SNe 2002ap and 1998bw. Spectroscopically SN 2004aw provides a link between a normal SN Ic like SN 1994I and the group of broad-lined SNe Ic. The spectral evolution is rather slow, with a spectrum at day +64 being still predominantly photospheric. The shape of the nebular [O-I] lambda lambda 6300, 6364 line indicates a highly aspherical explosion. Helium cannot be unambiguously identified in the spectra, even in the near-IR. Using an analytical description of the light-curve peak we find that the total mass of the ejecta in SN 2004aw is 3.5-8.0 M-circle dot, significantly larger than that in SN 1994I, although not as large as in SN 1998bw. The same model suggests that about 0.3 M-circle dot of Ni-56 has been synthesized in the explosion. No connection to a GRB can be firmly established.
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    SOAR/Goodman Spectroscopic Assessment of Candidate Counterparts of the LIGO/Virgo Event GW190814*
    (2022) Tucker, D. L.; Wiesner, M. P.; Allam, S. S.; Soares-Santos, M.; Bom, C. R.; Butner, M.; Garcia, A.; Morgan, R.; Olivares E, F.; Palmese, A.; Santana-Silva, L.; Shrivastava, A.; Annis, J.; Garcia-Bellido, J.; Gill, M. S. S.; Herner, K.; Kilpatrick, C. D.; Makler, M.; Sherman, N.; Amara, A.; Lin, H.; Smith, M.; Swann, E.; Arcavi, I; Bachmann, T. G.; Bechtol, K.; Berlfein, F.; Briceno, C.; Brout, D.; Butler, R. E.; Cartier, R.; Casares, J.; Chen, H-Y; Conselice, C.; Contreras, C.; Cook, E.; Cooke, J.; Dage, K.; D'Andrea, C.; Davis, T. M.; de Carvalho, R.; Diehl, H. T.; Dietrich, J. P.; Doctor, Z.; Drlica-Wagner, A.; Drout, M.; Farr, B.; Finley, D. A.; Fishbach, M.; Foley, R. J.; Forster-Buron, F.; Fosalba, P.; Friedel, D.; Frieman, J.; Frohmaier, C.; Gruendl, R. A.; Hartley, W. G.; Hiramatsu, D.; Holz, D. E.; Howell, D. A.; Kawash, A.; Kessler, R.; Kuropatkin, N.; Lahav, O.; Lundgren, A.; Lundquist, M.; Malik, U.; Mann, A. W.; Marriner, J.; Marshall, J. L.; Martinez-Vazquez, C. E.; McCully, C.; Menanteau, F.; Meza, N.; Narayan, G.; Neilsen, E.; Nicolaou, C.; Nichol, R.; Paz-Chinchon, F.; Pereira, M. E. S.; Pineda, J.; Points, S.; Quirola-Vasquez, J.; Rembold, S.; Rest, A.; Rodriguez, O.; Romer, A. K.; Sako, M.; Salim, S.; Scolnic, D.; Smith, J. A.; Strader, J.; Sullivan, M.; Swanson, M. E. C.; Thomas, D.; Valenti, S.; Varga, T. N.; Walker, A. R.; Weller, J.; Wood, M. L.; Yanny, B.; Zenteno, A.; Aguena, M.; Andrade-Oliveira, F.; Bertin, E.; Brooks, D.; Burke, D. L.; Rosell, A. Carnero; Kind, M. Carrasco; Carretero, J.; Costanzi, M.; da Costa, L. N.; De Vicente, J.; Desai, S.; Everett, S.; Ferrero, I; Flaugher, B.; Gaztanaga, E.; Gerdes, D. W.; Gruen, D.; Gschwend, J.; Gutierrez, G.; Hinton, S. R.; Hollowood, D. L.; Honscheid, K.; James, D. J.; Kuehn, K.; Lima, M.; Maia, M. A. G.; Miquel, R.; Ogando, R. L. C.; Pieres, A.; Malagon, A. A. Plazas; Rodriguez-Monroy, M.; Sanchez, E.; Scarpine, V; Schubnell, M.; Serrano, S.; Sevilla-Noarbe, I; Suchyta, E.; Tarle, G.; To, C.; Zhang, Y.
    On 2019 August 14 at 21:10:39 UTC, the LIGO/Virgo Collaboration (LVC) detected a possible neutron star-black hole merger (NSBH), the first ever identified. An extensive search for an optical counterpart of this event, designated GW190814, was undertaken using the Dark Energy Camera on the 4 m Victor M. Blanco Telescope at the Cerro Tololo Inter-American Observatory. Target of Opportunity interrupts were issued on eight separate nights to observe 11 candidates using the 4.1 m Southern Astrophysical Research (SOAR) telescope's Goodman High Throughput Spectrograph in order to assess whether any of these transients was likely to be an optical counterpart of the possible NSBH merger. Here, we describe the process of observing with SOAR, the analysis of our spectra, our spectroscopic typing methodology, and our resultant conclusion that none of the candidates corresponded to the gravitational wave merger event but were all instead other transients. Finally, we describe the lessons learned from this effort. Application of these lessons will be critical for a successful community spectroscopic follow-up program for LVC observing run 4 (O4) and beyond.
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    Supernova 2011db near Pgc 49027 = Psn 13490590+1714005
    (2011) Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan, Marcio; Beshore, E. C.; Larson, S. M.; Christensen, E.; Tomasella, L.; Ochner, P.; Valenti, S.; Benetti, S.; Pastorello, A.
    Report the Catalina Real-time Transient Survey's discovery of an apparent supernova in unfiltered survey images: SN 2011 UT R.A. (2000.0) Decl. Mag. Offset 2011db May 12.30 13 49 05.90 +17 14 00.5 17.4 6".4 E, 17".1 S This variable was designated PSN J13490590+1714005 when posted at the Central Bureau's TOCP webpage and is here designated SN 2011db based on the spectroscopic report below. Further magnitudes for 2011db: Apr. 25.22 UT, [20.0 (Catalina Sky Survey); May 13.357, 17.2 (Joseph Brimacombe, Cairns, Australia; from six stacked 1200-s images taken remotely using a 51-cm RCOS telescope + red filter + STL11K camera at New Mexico Skies Observatory near Mayhill, NM, U.S.A.; position end figures 05s.95, 13'59".6, which is near PGC 49027; his image is posted at the following website URL: http://www.flickr.com/photos/43846774@N02/5725585922/). L. Tomasella, P. Ochner, S. Valenti, and S. Benetti, Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova; and A. Pastorello, Dipartimento di Astronomia, Universita di Padova, on behalf of a larger collaboration, report that a spectrogram (range 390-810 nm; resolution 2.2 nm) of PSN 13490590+1714005 = SN 2011db, obtained on May 25.89 UT by the Service Telescope Operator Team with the Ekar-Copernicus 1.82-m telescope (+ AFOSC), is a type-II supernova, similar to SN 2007od (Inserra et al. 2011, posted at website URL http://lanl.arxiv.org/abs/1102.5468) at a couple of weeks after explosion....
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    Supernova 2011dc = Psn 14585651+6554083
    (2011) Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan, Marcio; Beshore, E. C.; Larson, S. M.; Christensen, E.; Tomasella, L.; Ochner, P.; Valenti, S.; Benetti, S.; Pastorello, A.
    Report the Catalina Real-time Transient Survey's discovery of an apparent supernova in unfiltered Catalina Sky Survey images: SN 2011 UT R.A. (2000.0) Decl. Mag. Offset 2011dc May 14.32 14 58 56.51 +65 54 08.3 17.0 9".5 W, 2".0 S This variable was designated PSN 14585651+6554083 when posted at the Central Bureau's TOCP webpage and is here designated SN 2011dc based on the spectroscopic report below. Further magnitudes for 2011dc: Apr. 2.37 UT, [19.0 (Catalina Sky Survey); May 15.237, 17.1 (Joseph Brimacombe, Cairns, Australia; from four stacked 1200-s images taken remotely using a 51-cm RCOS telescope + red filter + STL11K camera at New Mexico Skies Observatory near Mayhill, NM, U.S.A.; position end figures 56s.5, 07".8). Brimacombe's image is posted at http://www.flickr.com/photos/43846774@N02/5729478332/. L. Tomasella, P. Ochner, S. Valenti, and S. Benetti, Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova; and A. Pastorello, Dipartimento di Astronomia, Universita di Padova, on behalf of a larger collaboration, report that a noisy spectrogram (range 390-810 nm; resolution 2.2 nm) of PSN 14585651+6554083 = SN 2011dc, obtained on May 26.03 UT under poor weather conditions by the Service Telescope Operator Team with the Ekar-Copernicus 1.82-m telescope (+ AFOSC), suggests that 2011dc is likely a type-I supernova; if a broad absorption measured at 644.0 nm is identified with Si II 635.5-nm, the redshift of 2011dc is between 0.04 and 0.05....
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    Supernova 2011dj in Pgc 45427 = Psn J13070669-0110440
    (2011) Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan, Marcio; Beshore, E. C.; Larson, S. M.; Christensen, E.; Baroni, S.; Buzzi, L.; Concari, P.; Foglia, S.; Galli, G.; Tombelli, M.; Tomasella, L.; Ochner, P.; Valenti, S.; Benetti, S.; Pastorello, A.
    Report the Catalina Real-time Transient Survey's discovery of an apparent supernova in unfiltered Catalina Sky Survey (CSS) images, as tabulated below. The variable was designated PSN J13070669-0110440 when posted on the Central Bureau's TOCP webpage and is here designated SN 2011dj based on the spectroscopic report below. SN 2011 UT R.A. (2000.0) Decl. Mag. Offset 2011dj June 4.21 13 07 06.69 - 1 10 44.0 15.8 15".7 E, 7".2 S Additional CCD magnitudes for 2011dj: May 25.28 UT, [20.0 (CSS); June 4.563, R = 15.7 (Joseph Brimacombe, Coral Towers Observatory, Cairns, Australia; 30-cm reflector + STL6K camera; five 600-s stacked images; position end figures 06s.67, 45".5); 7.567, R = 15.1 (S. Baroni, L. Buzzi, P. Concari, S. Foglia, G. Galli, and M. Tombelli; remotely using a 0.18-m f/2.8 reflector at the Tzec Maun Observatory, Moorook, Australia; position end figures 06s.69, 45".0); 9.424, R = 15.4 (Baroni et al.). Foglia adds that nothing is visible at the position of 2011dj in NEAT images from 2002 Apr. 14 and 2003 Apr. 9 (no limiting magnitudes provided). Brimacombe's image is posted at website URL http://www.flickr.com/photos/43846774@N02/5799770906/. Foglia notes that their image from June 7 is posted at the following website URL: URL http://www.apan.it/pianetini/pub/psn/pgc45427.htm. L. Tomasella, P. Ochner, S. Valenti, and S. Benetti, Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova; and A. Pastorello, Dipartimento di Astronomia, Universita di Padova, on behalf of a larger collaboration, report that a spectrogram (range 390-810 nm; resolution 2.2 nm) of PSN J13070669-0110440 = SN 2011dj, obtained on June 6.87 UT with the Ekar-Copernicus 1.82-m telescope (+ AFOSC), shows it to be a type-Ia supernova, a couple of days before maximum....
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    Supernova 2011dr in Pgc 64099 = Psn J20062026-4245581
    (2011) Howerton, S.; Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan, Marcio; McNaught, R. H.; Garradd, G.; Beshore, E. C.; Larson, S. M.; Christensen, E.; Valenti, S.; Benetti, S.
    Report the discovery of an apparent supernova in public images from the Siding Spring Survey (SSS), with the discovery observation tabulated below: SN 2011 UT R.A. (2000.0) Decl. Mag. Offset 2011dr May 25.82 20 06 20.26 -42 45 58.1 17.8 9".7 W, 7".0 S The variable was designated PSN J20062026-4245581 when posted on the Central Bureau's TOCP webpage and is here designated SN 2011dr based on the spectroscopic confirmation below. Additional magnitudes for 2011dr: Apr. 30.73 UT, [19.2 (SSS); May 26.732, 17.0 (Joseph Brimacombe, Coral Towers Observatory, Cairns, Australia; 30-cm telescope + STL6K camera + red filter; position end figures 20s.28, 56".5). Brimacombe's image is posted at website URL http://www.flickr.com/photos/43846774@N02/5763117132/. S. Valenti and S. Benetti, Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova, on behalf of a larger collaboration, report that a spectrogram (range 330-750 nm; resolution 1.5 nm) of PSN J20062026-4245581 = SN 2011dr, obtained on June 26.40 UT with the European Southern Observatory's New Technology Telescope (+ EFOSC), is that of a type-IIP supernova. After cross-correlation with a library of supernova spectra via the "GELATO" code (Harutyunyan et al. 2008, A.Ap. 488, 383; available at website URL https://gelato.tng.iac.es/login.cgi), the spectrum of SN 2011dr appears to be very similar to that of SN 1999gi (Leonard et al. 2002, A.J. 124, 2490) at one month after explosion....
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    Supernova 2011ds = Psn J20022093-2013134
    (2011) Howerton, S.; Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan, Marcio; McNaught, R. H.; Garradd, G.; Beshore, E. C.; Larson, S. M.; Christensen, E.; Valenti, S.; Benetti, S.
    Report the discovery of an apparent supernova in public images from the Catalina Sky Survey; it was confirmed in images obtained with the Siding Spring Survey (SSS). SN 2011 UT R.A. (2000.0) Decl. Mag. Offset 2011ds May 13.42 20 02 20.93 -20 13 13.4 16.6 6" W, 17" N The variable was designated PSN J20022093-2013134 when posted at the Central Bureau's TOCP webpage and is here designated SN 2011ds based on the spectroscopic confirmation that is detailed below. Further magnitudes for 2011ds: Apr. 11.74 [19.0 (SSS); May 14.69, 16.6 (SSS); 15.721, 16.6 (Joseph Brimacombe, Coral Towers Observatory, Cairns, Australia, 30-cm telescope + STL6K camera + red filter; position end figures 20s.92, 12".8). Brimacombe's image is posted at URL http://www.flickr.com/photos/43846774@N02/5724709574/. S. Valenti and S. Benetti, Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova, on behalf of a larger collaboration, report that a low-signal-to-noise spectrogram (range 330-750 nm; resolution 1.5 nm) of PSN J20022093-2013134 = SN 2011ds, obtained on June 26.43 UT with the European Southern Observatory's New Technology Telescope (+ EFOSC2), is consistent with that of a type-II supernova. The spectrum indeed shows strong hydrogen H-alpha at 669.1 nm, mainly in emission with a full-width-at-half-maximum of about 7400 km/s....
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    Supernova 2011fz in UGC 12271 = Psn J22582030+0217299
    (2011) Howerton, S.; Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan, Marcio; McNaught, R. H.; Garradd, G.; Beshore, E. C.; Larson, S. M.; Christensen, E.; Valenti, S.; Benetti, S.; Tomasella, L.; Ochner, P.; Pastorello, A.
    Report the discovery of an apparent supernova in public images from the Catalina Sky Survey (CSS). SN 2011 UT R.A. (2000.0) Decl. Mag. Offset 2011fz Sep. 18.28 22 58 20.30 + 2 17 29.9 16.6 13".3 W, 23".0 S The new object was designated PSN J22582030+0217299 when it was posted at the Central Bureau's TOCP webpage and is here designated SN 2011fz based on the spectroscopic report below. Additional unfiltered CCD magnitudes for 2011fz: July 2.38 UT, 19.0 (CSS); Sept. 19.381, 17.9 (Joseph Brimacombe, Cairns, Australia; position end figures 20s.26, 29".2; image posted at website URL http://www.flickr.com/photos/43846774@N02/6170077719/); 19.89, 17.1 (Nick James, Chelmsford, Essex, England; Celestron 11 telescope + ST9XE camera; position end figures 20s.26, 29".0; UCAC-3 reference stars). S. Valenti, S. Benetti, L. Tomasella, and P. Ochner, Osservatorio Astronomico di Padova, Istituto Nazionale di Astrofisica; and A. Pastorello, Dipartimento di Astronomia, Universita di Padova, on behalf of a larger collaboration, report that a spectrogram of PSN J22582030+0217299 = SN 2011fz, obtained on Sept. 24.95 UT, suggests that it is a type-Ib/c supernova observed several weeks after maximum. Using the distance module of 34.14 for UGC 12271 (Mould et al. 2000, Ap.J. 529, 786; via the NED website) and an apparent magnitude of 17.7, 2011fz has an absolute magnitude of -16.45, which is consistent with magnitudes of type-Ib/c supernovae at this phase....
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    Supernova 2011ga in Pgc 69458 = Psn J22402742+0311580
    (2011) Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan, Marcio; Beshore, E. C.; Larson, S. M.; Christensen, E.; Valenti, S.; Benetti, S.; Tomasella, L.; Ochner, P.; Pastorello, A.; Marion, G. H.
    Report the discovery of an apparent supernova in unfiltered Catalina Sky Survey (CSS) images: SN 2011 UT R.A. (2000.0) Decl. Mag. Offset 2011ga Sep. 18.25 22 40 27.42 + 3 11 58.0 17.3 18".2 W, 7".4 N The new object was designated PSN J22402742+0311580 when it was posted at the Central Bureau's TOCP webpage and is here designated SN 2011ga based on the spectroscopic report below. Additional CCD magnitudes for 2011ga (unfiltered unless noted otherwise: July 2.38 UT, [19.3 (CSS); Sept. 19.179, 16.5 (Joseph Brimacombe, Cairns, Australia; infrared filter, wavelength > 700 nm; image posted at URL http://www.flickr.com/photos/43846774@N02/6177998402/); 19.320, 17.2 (Brimacombe; position end figures 27s.38, 58".9; image posted at website URL http://www.flickr.com/photos/43846774@N02/6168832131/). S. Valenti, S. Benetti, L. Tomasella, and P. Ochner, Osservatorio Astronomico di Padova, Istituto Nazionale di Astrofisica; and A. Pastorello, Dipartimento di Astronomia, Universita di Padova, on behalf of a larger collaboration, report that a spectrogram of PSN J22402742+0311580 = SN 2011ga, obtained on Sept. 24.91 UT, suggests that it is a type-Ia supernova observed close to B-band maximum. The velocity of the ejected material, as deduced from the position of the minimum of the Si II lines, is about 10600 km/s. G. H. Marion, Harvard-Smithsonian Center for Astrophysics (CfA), on behalf of the CfA Supernova Group, report that a spectrum (range 340-740 nm) of PSN J22402742+0311580 = 2011ga was obtained on Sept. 27 UT by Marion with the F. L. Whipple Observatory 1.5-m telescope (+ FAST). Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) shows that the object is a type-Ia supernova a few days after maximum light. The best-fit template spectrum is that of SN 2003du at +2 days. The velocity of the Si II 635.5-nm feature is estimated to be approximately 10800 km/s, using the SNID estimated redshift of z = 0.040....
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    Supernova 2011gb = Psn J01334294+3448371
    (2011) Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan, Marcio; Beshore, E. C.; Larson, S. M.; Christensen, E.; Denisenko, D.; Brimacombe, J.; Valenti, S.; Benetti, S.; Tomasella, L.; Ochner, P.; Pastorello, A.
    Report the discovery of an apparent supernova in unfiltered Catalina Sky Survey (CSS) images: SN 2011 UT R.A. (2000.0) Decl. Mag. Offset 2011gb Sep. 24.30 1 33 42.94 +34 48 37.1 16.1 4".5 W, 1".1 S The new object was designated PSN J01334294+3448371 when it was posted at the Central Bureau's TOCP webpage and is here designated SN 2011gb based on the spectroscopic report below. Additional CCD magnitudes for 2011gb (unfiltered unless noted otherwise): Jan. 16.23, [18.5 (CSS); Sept. 24.850, 15.9 (D. Denisenko, Moscow, Russia; 0.20-m f/5 reflector + Meade DSI Pro II camera; position end figures 42s.84, 36".8; image posted at the following website URL: http://pics.livejournal.com/bigdenru/pic/000a957p/); 24.897, 15.5 (Paolo Corelli, Pagnacco, Italy; 0.45-m f/4.5 telescope; position end figures 42s.8, 36".8; nearby galaxy centered at position end figures 43s.35, 37".9); 25.187, 16.3 (J. Brimacombe, Cairns, Australia; position end figures 42s.86, 37".0; image posted at URL http://www.flickr.com/photos/43846774@N02/6186780582/); 26.875, 16.3 (Nick James, Chelmsford, Essex, England; Celestron 11 telescope + ST9XE camera; position end figures 42s.84, 36".9; UCAC-3 reference stars). S. Valenti, S. Benetti, L. Tomasella, and P. Ochner, Osservatorio Astronomico di Padova, Istituto Nazionale di Astrofisica; and A. Pastorello, Dipartimento di Astronomia, Universita di Padova, on behalf of a larger collaboration, report that a spectrogram of PSN J01334294+3448371 = SN 2011gb, obtained on Sept. 25.06 UT, suggests that it is a type-Ia supernova observed a few weeks after B-band maximum at a redshift z = 0.014....
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    Supernova 2011gf = Psn J21122427-0748521
    (2011) Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan, Marcio; Beshore, E. C.; Larson, S. M.; Christensen, E.; Valenti, S.; Benetti, S.; Tomasella, L.; Ochner, P.; Pastorello, A.; Marion, G. H.
    Report the discovery of an apparent supernova in unfiltered Catalina Sky Survey images: SN 2011 UT R.A. (2000.0) Decl. Mag. Offset 2011gf Sep. 18.19 21 12 24.27 - 7 48 52.1 16.6 23".5 E, 21".8 N This variable was designated PSN J21122427-0748521 when it was posted on the Central Bureau's TOCP webpage and is here designated SN 2011gf based on the spectroscopic report below. Joseph Brimacombe, Cairns, Australia, reports unfiltered CCD mag 16.1 and position end figures 24s.31, 51".8 from an image taken on Sept. 19.266 UT; he has posted his image at the following website URL: http://www.flickr.com/photos/43846774@N02/6167975455/. S. Valenti, S. Benetti, L. Tomasella, and P. Ochner, Osservatorio Astronomico di Padova, Istituto Nazionale di Astrofisica; and A. Pastorello, Dipartimento di Astronomia, Universita di Padova, on behalf of a larger collaboration, report that a spectrogram (range 360-810 nm; resolution 2.2 nm) of PSN J21122427-0748521 = SN 2011gf, obtained on Sept. 25.90 UT, suggestss that it is a type-Ia supernova. Cross-correlation with a library of supernova spectra via the "GELATO" code (Harutyunyan et al. 2008, A.Ap. 488, 383; available at URL https://gelato.tng.iac.es/login.cgi), suggest a normal type-Ia supernova close to the B-band maximum at a redshift of z = 0.0277 (Sloan Digital Sky Survey, via the NED website). The expansion velocity deduced from the Si II 635.5-nm minimum is about 11100 km/s. G. H. Marion, Harvard-Smithsonian Center for Astrophysics (CfA), on behalf of the CfA Supernova Group, report that a spectrum (range 340-740 nm) of PSN J21122427-0748521 = 2011gf was obtained on Sept. 27 UT by Marion with the F. L. Whipple Observatory 1.5-m telescope (+ FAST). Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) shows that 2011gf is a type-Ia supernova a few days after maximum light. The best-fit template spectrum is that of SN 2007F at +4 days. The velocity of the Si II 635.5-nm feature is estimated to be approximately 11600 km/s, using the SNID estimated redshift of z = 0.027....
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    Supernova 2011gg = Psn J00462108-0909277
    (2011) Drake, A. J.; Djorgovski, S. G.; Mahabal, A.; Graham, M. J.; Williams, R.; Prieto, J. L.; Catelan, Marcio; Beshore, E. C.; Larson, S. M.; Christensen, E.; Valenti, S.; Benetti, S.; Tomasella, L.; Ochner, P.; Pastorello, A.
    Report the discovery of an apparent supernova in unfiltered Catalina Sky Survey (CSS) images: SN 2011 UT R.A. (2000.0) Decl. Mag. Offset 2011gg Sep. 20.32 00 46 21.08 - 9 09 27.7 17.6 4".5 W, 1".1 S This variable was designated PSN J00462108-0909277 when it was posted on the Central Bureau's TOCP webpage and is here designated SN 2011gg based on the spectroscopic report below. Further unfiltered CCD magnitudes for 2011gg: Sept. 24.34 UT, 17.4 (CSS); 27.407, 16.9 (Joseph Brimacombe, Cairns, Australia; position end figures 21s.05, 28".6; image posted at the following website URL: http://www.flickr.com/photos/43846774@N02/6191346245/). S. Valenti, S. Benetti, L. Tomasella, and P. Ochner, Osservatorio Astronomico di Padova, Istituto Nazionale di Astrofisica; and A. Pastorello, Dipartimento di Astronomia, Universita di Padova, on behalf of a larger collaboration, report that a spectrogram (range 360-810 nm; resolution 2.2 nm) of PSN J00462108-0909277 = SN 2011gg, obtained on Sept. 26.01 UT, suggests that it is a type-Ia supernova. Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J. 666, 1024) suggests a normal type-Ia supernova about one week before the B-band maximum at a redshift z = 0.055. The expansion velocity derived from the Si II 635.5-nm minimum is then about 10500 km/s....