Browsing by Author "Annunziatella, M."

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    CLASH-VLT : The stellar mass function and stellar mass density profile of the z = 0.44 cluster of galaxies MACS J1206.2-0847
    (2014) Annunziatella, M.; Biviano, A.; Mercurio, A.; Nonino, M.; Rosati, P.; Balestra, I.; Presotto, V.; Girardi, M.; Gobat, R.; Infante Lira, Leopoldo
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    CLASH-VLT: spectroscopic confirmation of z=6.11 quintuply lensed galaxy in the Frontier Fields cluster RXC J2248.7-4431
    (2013) Balestra, I.; Vanzella, E.; Rosati, P.; Monna, A.; Grillo, C.; Nonino, M.; Mercurio, A.; Biviano, A.; Bradley, L.; Coe, D.; Fritz, A.; Postman, M.; Seitz, S.; Scodeggio, M.; Tozzi, P.; Zhengll, W.; Ziegler, B.; Zitrin, A.; Annunziatella, M.; Bartelmann, M.; Benitez, N.; Broadhurst, T.; Bouwens, R.; Czoske, O.; Donahue, M.; Ford, H.; Girardi, M.; Infante, L.; Jouvel, S.; Kelson, D.; Koekemoer, A.; Kuchner, U.; Lemze, D.; Lombardi, M.; Maier, C.; Medezinski, E.; Melchior, P.; Meneghetti, M.; Merten, J.; Molino, A.; Moustakas, L.; Presotto, V.; Smit, R.; Umetsu, K.
    We present VIsible Multi-Object Spectrograph (VIMOS) observations of a z similar to 6 galaxy quintuply imaged by the Frontier Fields galaxy cluster RXC J2248.7-4431 (z = 0.348). This sub-L*, high-z galaxy has been recently discovered by Monna et al. (2013) using dropout techniques with the 16-band HST photometry acquired as part of the Cluster Lensing And Supernova survey with Hubble (CLASH). Obtained as part of the CLASH-VLT survey, the VIMOS medium-resolution spectra of this source show a very faint continuum between similar to 8700 angstrom and similar to 9300 angstrom and a prominent emission line at 8643 angstrom, which can be readily identified with Lyman-alpha at z = 6.110 +/- 0.002. The emission line exhibits an asymmetric profile, with a more pronounced red wing. The rest-frame equivalent width of the line is EW = 79 +/- 10 angstrom, relatively well constrained thanks to the detection of the UV continuum, which is rarely achieved for a sub-L* galaxy at this redshift. After correcting for magnification, the star formation rate (SFR) estimated from the Ly alpha line is SFR(Ly alpha) = 11 M-circle dot yr(-l) and that estimated from the UV data is SFR(UV) = 3 M-circle dot yr(-1). We estimate that the effective radius of the source is R-e less than or similar to 0.4 kpc, which implies a star formation surface mass density Sigma(SFR) > 6 M(circle dot)yr(-1) kpc(-2) and, using the Kennicutt-Schmidt relation, a gas surface mass density Sigma(gas) > 10(3) M(circle dot)pc(-2). Our results support the idea that this magnified, distant galaxy is a young and compact object with luminosity 0.4 L* at z = 6, when the Universe was just 1 Gyr old, with a similar amount of mass in gas and stars. In the spirit of the Frontier Fields initiative, we also publish the redshifts of several multiply imaged sources and other background objects, which will help improving the strong-lensing model of this galaxy cluster.
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    The deep Chandra survey in the SDSS J1030+0524 field
    (2020) Nanni, R.; Gilli, R.; Vignali, C.; Mignoli, M.; Peca, A.; Marchesi, S.; Annunziatella, M.; Brusa, M.; Calura, F.; Cappelluti, N.; Chiaberge, M.; Comastri, A.; Iwasawa, K.; Lanzuisi, G.; Liuzzo, E.; Marchesini, D.; Prandoni, I.; Tozzi, P.; Vito, F.; Zamorani, G.; Norman, C.
    We present the X-ray source catalog for the similar to 479 ks Chandra exposure of the SDSS J1030+0524 field, which is centered on a region that shows the best evidence to date of an overdensity around a z > 6 quasar, and also includes a galaxy overdensity around a Compton-thick Fanaroff-Riley type II (FRII) radio galaxy at z = 1.7. Using wavdetect for initial source detection and ACIS Extract for source photometry and significance assessment, we create preliminary catalogs of sources that are detected in the full (0.5-7.0 keV), soft (0.5-2.0 keV), and hard (2-7 keV) bands, respectively. We produce X-ray simulations that mirror our Chandra observation to filter our preliminary catalogs and achieve a completeness level of > 91% and a reliability level of similar to 95% in each band. The catalogs in the three bands are then matched into a final main catalog of 256 unique sources. Among them, 244, 193, and 208 are detected in the full, soft, and hard bands, respectively. The Chandra observation covers a total area of 335 arcmin(2) and reaches flux limits over the central few square arcmins of similar to 3 x 10(-16), 6 x 10(-17), and 2 x 10(-16) erg cm(-2) s(-1) in the full, soft, and hard bands, respectively This makes J1030 field the fifth deepest extragalactic X-ray survey to date. The field is part of the Multiwavelength Survey by Yale-Chile (MUSYC), and is also covered by optical imaging data from the Large Binocular Camera (LBC) at the Large Binocular Telescope (LBT), near-infrared imaging data from the Canada France Hawaii Telescope WIRCam (CFHT/WIRCam), and Spitzer IRAC. Thanks to its dense multi-wavelength coverage, J1030 represents a legacy field for the study of large-scale structures around distant accreting supermassive black holes. Using a likelihood ratio analysis, we associate multi-band (r, z, J, and 4.5 mu m) counterparts for 252 (98.4%) of the 256 Chandra sources, with an estimated reliability of 95%. Finally, we compute the cumulative number of sources in each X-ray band, finding that they are in general agreement with the results from the Chandra Deep Fields.