DSpace Angular :: Browsing by Author "Magnelli, B."

Browsing by Author "Magnelli, B."

Now showing 1 - 16 of 16

An ALMA survey of submillimetre galaxies in the COSMOS field : Physical properties derived from energy balance spectral energy distribution modelling
(2017) Miettinen, O.; Delvecchio, I.; Smolčić, V.; Aravena, M.; Brisbin, D.; Karim, A.; Magnelli, B.; Novak, M.; Schinnerer, E.; Padilla, Nelson; Albrecht, M.; Aussel, H.; Bertoldi, F.; Capak, P.; Casey, C.; Hayward, C.; Ilbert , O.; Intema, H.; Jiang, C.; Le Fèvre, O.; McCracken, H.; Munõz Arancibia A.; Navarrete, F.; Riechers, D.|Salvato M.; Scott, K.; Sheth, K.; Tasca, L.
An ALMA survey of submillimetre galaxies in the COSMOS field : The extent of the radio-emitting region revealed by 3 GHz imaging with the Very Large Array
(2017) Miettinen, O.; Novak, M.; Smolčić, V.; Delvecchio, I.; Aravena, M.; Brisbin, D.; Karim, A.; Murphy, E.; Schinnerer, E.; Padilla, Nelson; Albrecht, M.; Aussel, H.; Bertoldi, F.; Capak, P.; Casey, C.; Civano, F.; Hayward, C.; Herrera Ruiz, N.; Ilbert, O.; Jiang, C.; Laigle, C.; Le Fèvre, O.; Magnelli, B.; Marchesi, S.; McCracken, H.; Middelberg, E.; Muñoz Arancibia, A.; Navarrete, F.; Riechers, D.; Salvato, M.; Scott, K.; Sheth, K.; Tasca, L.; Bondi, M.; Zamorani, G.
Enhanced star formation rates in AGN hosts with respect to inactive galaxies from PEP-Herschel observations
(2012) Santini, P.; Rosario, D. J.; Shao, L.; Lutz, D.; Maiolino, R.; Alexander, D. M.; Altieri, B.; Andreani, P.; Aussel, H.; Bauer, F. E.; Berta, S.; Bongiovanni, A.; Brandt, W. N.; Brusa, M.; Cepa, J.; Cimatti, A.; Daddi, E.; Elbaz, D.; Fontana, A.; Schreiber, N. M. Foerster; Genzel, R.; Grazian, A.; Le Floc'h, E.; Magnelli, B.; Mainieri, V.; Nordon, R.; Garcia, A. M. Perez; Poglitsch, A.; Popesso, P.; Pozzi, F.; Riguccini, L.; Rodighiero, G.; Salvato, M.; Sanchez-Portal, M.; Sturm, E.; Tacconi, L. J.; Valtchanov, I.; Wuyts, S.
We compare the average star formation (SF) activity in X-ray selected AGN hosts with a mass-matched control sample of inactive galaxies, including both star forming and quiescent sources, in the 0.5 < z < 2.5 redshift range. Recent observations carried out by PACS, the 60-210 mu m photometric camera on board the Herschel Space Observatory, in GOODS-S, GOODS-N and COSMOS allow us to obtain an unbiased estimate of the far-IR luminosity, and hence of the SF properties, of the two samples. Accurate AGN host stellar mass estimates are obtained by decomposing their total emission into the stellar and the nuclear components. We report evidence of a higher average SF activity in AGN hosts with respect to the control sample of inactive galaxies. The level of SF enhancement is modest (similar to 0.26 dex at similar to 3 sigma confidence level) at low X-ray luminosities (L-X less than or similar to 10(43.5) erg s(-1)) and more pronounced (0.56 dex at >10 sigma confidence level) in the hosts of luminous AGNs. However, when comparing to star forming galaxies only, AGN hosts are found broadly consistent with the locus of their "main sequence". We investigate the relative far-IR luminosity distributions of active and inactive galaxies, and find a higher fraction of PACS detected, hence normal and highly star forming systems among AGN hosts. Although different interpretations are possible, we explain our findings as a consequence of a twofold AGN growth path: faint AGNs evolve through secular processes, with instantaneous AGN accretion not tightly linked to the current total SF in the host galaxy, while the luminous AGNs co-evolve with their hosts through periods of enhanced AGN activity and star formation, possibly through major mergers. While an increased SF activity with respect to inactive galaxies of similar mass is expected in the latter, we interpret the modest SF offsets measured in low-L-X AGN hosts as either a) generated by non-synchronous accretion and SF histories in a merger scenario or b) due to possible connections between instantaneous SF and accretion that can be induced by smaller scale (non-major merger) mechanisms. Far-IR luminosity distributions favour the latter scenario.
GOODS-ALMA 2.0: Source catalog, number counts, and prevailing compact sizes in 1.1 mm galaxies
(2022) Gómez-Guijarro, C.; Elbaz, D.; Xiao, M.; Béthermin, M.; Franco, M.; Magnelli, B.; Daddi, E.; Dickinson, M.; Demarco, R.; Inami, H.; Rujopakarn, W.; Magdis, G. E.; Shu, X.; Chary, R.; Zhou, L.; Alexander, D. M.; Bournaud, F.; Ciesla, L.; Ferguson, H. C.; Finkelstein, S. L.; Giavalisco, M.; Iono, D.; Juneau, S.; Kartaltepe, J. S.; Lagache, G.; Le Floc'h, E.; Leiton, R.; Lin, L.; Motohara, K.; Mullaney, J.; Okumura, K.; Pannella, M.; Papovich, C.; Pope, A.; Sargent, M. T.; Silverman, J. D.; Treister, E.; Wang, T.
Submillimeter/millimeter observations of dusty star-forming galaxies with the Atacama Large Millimeter/submillimeter Array (ALMA) have shown that dust continuum emission generally occurs in compact regions smaller than the stellar distribution. However, it remains to be understood how systematic these findings are. Studies often lack homogeneity in the sample selection, target discontinuous areas with inhomogeneous sensitivities, and suffer from modest uv coverage coming from single array configurations. GOODS-ALMA is a 1.1 mm galaxy survey over a continuous area of 72.42 arcmin(2) at a homogeneous sensitivity. In this version 2.0, we present a new low resolution dataset and its combination with the previous high resolution dataset from the survey, improving the uv coverage and sensitivity reaching an average of sigma = 68.4 mu Jy beam(-1). A total of 88 galaxies are detected in a blind search (compared to 35 in the high resolution dataset alone), 50% at S/N-peak >= 5 and 50% at 3.5 <= S/N-peak <= 5 aided by priors. Among them, 13 out of the 88 are optically dark or faint sources (H- or K-band dropouts). The sample dust continuum sizes at 1.1 mm are generally compact, with a median effective radius of R-e = 0 ''.10 +/- 0 ''.5 (a physical size of R-e = 0.73 +/- 0.29 kpc at the redshift of each source). Dust continuum sizes evolve with redshift and stellar mass resembling the trends of the stellar sizes measured at optical wavelengths, albeit a lower normalization compared to those of late-type galaxies. We conclude that for sources with flux densities S-1.1mm > 1 mJy, compact dust continuum emission at 1.1 mm prevails, and sizes as extended as typical star-forming stellar disks are rare. The S-1.1mm < 1 mJy sources appear slightly more extended at 1.1 mm, although they are still generally compact below the sizes of typical star-forming stellar disks.
GOODS-ALMA 2.0: Starbursts in the main sequence reveal compact star formation regulating galaxy evolution prequenching
(2022) Gomez-Guijarro, C.; Elbaz, D.; Xiao, M.; Kokorev, V., I; Magdis, G. E.; Magnelli, B.; Daddi, E.; Valentino, F.; Sargent, M. T.; Dickinson, M.; Bethermin, M.; Franco, M.; Pope, A.; Kalita, B. S.; Ciesla, L.; Demarco, R.; Inami, H.; Rujopakarn, W.; Shu, X.; Wang, T.; Zhou, L.; Alexander, D. M.; Bournaud, F.; Chary, R.; Ferguson, H. C.; Finkelstein, S. L.; Giavalisco, M.; Iono, D.; Juneau, S.; Kartaltepe, J. S.; Lagache, G.; Le Floc'h, E.; Leiton, R.; Leroy, L.; Lin, L.; Motohara, K.; Mullaney, J.; Okumura, K.; Pannella, M.; Papovich, C.; Treister, E.
Compact star formation appears to be generally common in dusty star-forming galaxies (SFGs). However, its role in the framework set by the scaling relations in galaxy evolution remains to be understood. In this work we follow up on the galaxy sample from the GOODS-ALMA 2.0 survey, an ALMA blind survey at 1.1 mm covering a continuous area of 72.42 arcmin(2) using two array configurations. We derived physical properties, such as star formation rates, gas fractions, depletion timescales, and dust temperatures for the galaxy sample built from the survey. There exists a subset of galaxies that exhibit starburst-like short depletion timescales, but they are located within the scatter of the so-called main sequence of SFGs. These are dubbed starbursts in the main sequence and display the most compact star formation and they are characterized by the shortest depletion timescales, lowest gas fractions, and highest dust temperatures of the galaxy sample, compared to typical SFGs at the same stellar mass and redshift. They are also very massive, accounting for similar to 60% of the most massive galaxies in the sample (log(M-*/M-circle dot) > 11.0). We find trends between the areas of the ongoing star formation regions and the derived physical properties for the sample, unveiling the role of compact star formation as a physical driver of these properties. Starbursts in the main sequence appear to be the extreme cases of these trends. We discuss possible scenarios of galaxy evolution to explain the results drawn from our galaxy sample. Our findings suggest that the star formation rate is sustained in SFGs by gas and star formation compression, keeping them within the main sequence even when their gas fractions are low and they are presumably on the way to quiescence.
GOODS-Herschel: the far-infrared view of star formation in active galactic nucleus host galaxies since z ∼ 3
(2012) Mullaney, J. R.; Pannella, M.; Daddi, E.; Alexander, D. M.; Elbaz, D.; Hickox, R. C.; Bournaud, F.; Altieri, B.; Aussel, H.; Coia, D.; Dannerbauer, H.; Dasyra, K.; Dickinson, M.; Hwang, H. S.; Kartaltepe, J.; Leiton, R.; Magdis, G.; Magnelli, B.; Popesso, P.; Valtchanov, I.; Bauer, F. E.; Brandt, W. N.; Del Moro, A.; Hanish, D. J.; Ivison, R. J.; Juneau, S.; Luo, B.; Lutz, D.; Sargent, M. T.; Scott, D.; Xue, Y. Q.
We present a study of the infrared properties of X-ray selected, moderate-luminosity (i.e. L-X = 10(42)-10(44) erg s(-1)) active galactic nuclei (AGNs) up to z approximate to 3, in order to explore the links between star formation in galaxies and accretion on to their central black holes. We use 100 and 160 mu m fluxes from GOODS-Herschel - the deepest survey yet undertaken by the Herschel telescope - and show that in the vast majority of cases (i.e. > 94 per cent) these fluxes are dominated by emission from the host galaxy. As such, these far-infrared bands provide an uncontaminated view of star formation in the AGN host galaxies. We find no evidence of any correlation between the X-ray and infrared luminosities of moderate AGNs at any redshift, suggesting that global star formation is decoupled from nuclear (i.e. AGN) activity in these galaxies. On the other hand, we confirm that the star formation rates of AGN hosts increase strongly with redshift, by a factor of 43(-18)(+27) from z < 0.1 to z = 2-3 for AGNs with the same range of X-ray luminosities. This increase is entirely consistent with the factor of 25-50 increase in the specific star formation rates (SSFRs) of normal, star-forming (i.e. main-sequence) galaxies over the same redshift range. Indeed, the average SSFRs of AGN hosts are only marginally (i.e. approximate to 20 per cent) lower than those of main-sequence galaxies at all surveyed redshifts, with this small deficit being due to a fraction of AGNs residing in quiescent (i.e. low SSFR) galaxies. We estimate that 79 +/- 10 per cent of moderate-luminosity AGNs are hosted in main-sequence galaxies, 15 +/- 7 per cent in quiescent galaxies and < 10 per cent in strongly starbursting galaxies. We derive the fractions of all main-sequence galaxies at z < 2 that are experiencing a period of moderate nuclear activity, noting that it is strongly dependent on galaxy stellar mass (M-stars), rising from just a few per cent at M-stars similar to 10(10) M-circle dot to greater than or similar to 20 per cent at M-stars >= 10(11) M-circle dot. Our results indicate that it is galaxy stellar mass that is most important in dictating whether a galaxy hosts a moderate-luminosity AGN. We argue that the majority of moderate nuclear activity is fuelled by internal mechanisms rather than violent mergers, which suggests that high-redshift disc instabilities could be an important AGN feeding mechanism.
Herschel FIR counterparts of selected Lyα emitters at z ∼ 2.2 Fast evolution since z ∼ 3 or missed obscured AGNs?
(2010) Bongiovanni, A.; Oteo, I.; Cepa, J.; Perez Garcia, A. M.; Sanchez-Portal, M.; Ederoclite, A.; Aguerri, J. A. L.; Alfaro, E. J.; Altieri, B.; Andreani, P.; Aparicio-Villegas, M. T.; Aussel, H.; Benitez, N.; Berta, S.; Broadhurst, T.; Cabrera-Cano, J.; Castander, F. J.; Cava, A.; Cervino, M.; Chulani, H.; Cimatti, A.; Cristobal-Hornillos, D.; Daddi, E.; Dominguez, H.; Elbaz, D.; Fernandez-Soto, A.; Schreiber, N. Foerster; Genzel, R.; Gomez, M. F.; Gonzalez Delgado, R. M.; Grazian, A.; Gruppioni, C.; Herreros, J. M.; Iglesias Groth, S.; Infante, L.; Lutz, D.; Magnelli, B.; Magdis, G.; Maiolino, R.; Marquez, I.; Martinez, V. J.; Masegosa, J.; Moles, M.; Molino, A.; Nordon, R.; del Olmo, A.; Perea, J.; Poglitsch, A.; Popesso, P.; Pozzi, F.; Prada, F.; Quintana, J. M.; Riguccini, L.; Rodighiero, G.; Saintonge, A.; Sanchez, S. F.; Santini, P.; Shao, L.; Sturm, E.; Tacconi, L.; Valtchanov, I.
Ly alpha emitters (LAEs) are seen everywhere in the redshift domain from local to z similar to 7. Far-infrared (FIR) counterparts of LAEs at different epochs could provide direct clues on dust content, extinction, and spectral energy distribution (SED) for these galaxies. We search for FIR counterparts of LAEs that are optically detected in the GOODS-North field at redshift z similar to 2.2 using data from the Herschel Space Telescope with the Photodetector Array Camera and Spectrometer (PACS). The LAE candidates were isolated via color-magnitude diagram using the medium-band photometry from the ALHAMBRA Survey, ancillary data on GOODS-North, and stellar population models. According to the fitting of these spectral synthesis models and FIR/optical diagnostics, most of them seem to be obscured galaxies whose spectra are AGN-dominated. From the analysis of the optical data, we have observed a fraction of AGN or composite over source total number of similar to 0.75 in the LAE population at z similar to 2.2, which is marginally consistent with the fraction previously observed at z = 2.25 and even at low redshift (0.2 < z < 0.45), but significantly different from the one observed at redshift similar to 3, which could be compatible either with a scenario of rapid change in the AGN fraction between the epochs involved or with a non detection of obscured AGN in other z = 2-3 LAE samples due to lack of deep FIR observations. We found three robust FIR (PACS) counterparts at z similar to 2.2 in GOODS-North. This demonstrates the possibility of finding dust emission in LAEs even at higher redshifts.
Herschel reveals the obscured star formation in HiZELS Hα emitters at z=1.47
(2013) Ibar, E.; Sobral, D.; Best, P. N.; Ivison, R. J.; Smail, I.; Arumugam, V.; Berta, S.; Bethermin, M.; Bock, J.; Cava, A.; Conley, A.; Farrah, D.; Geach, J.; Ikarashi, S.; Kohno, K.; Le Floc'h, E.; Lutz, D.; Magdis, G.; Magnelli, B.; Marsden, G.; Oliver, S. J.; Page, M. J.; Pozzi, F.; Riguccini, L.; Schulz, B.; Seymour, N.; Smith, A. J.; Symeonidis, M.; Wang, L.; Wardlow, J.; Zemcov, M.
We describe the far-infrared (far-IR; rest-frame 8-1000-mu m) properties of a sample of 443 H alpha-selected star-forming galaxies in the Cosmic Evolution Survey (COSMOS) and Ultra Deep Survey (UDS) fields detected by the High-redshift Emission Line Survey (HiZELS) imaging survey. Sources are identified using narrow-band filters in combination with broad-band photometry to uniformly select H alpha (and [O ii] if available) emitters in a narrow redshift slice at z = 1.47 +/- 0.02. We use a stacking approach in Spitzer-MIPS mid-IR, Herschel-PACS/SPIRE far-IR [from the PACS Evolutionary Prove (PEP) and Herschel Multi-tiered Extragalactic Survey (HerMES)] and AzTEC mm-wave images to describe their typical far-IR properties. We find that HiZELS galaxies with observed H alpha luminosities of L(H alpha)(obs) approximate to 10(8.1-9.1) L-circle dot ( approximate to 10(41.7-42.7) erg s(-1)) have bolometric far-IR luminosities of typical luminous IR galaxies, L(8-1000 mu m) approximate to 10(-0.006)(11.41)(+0.04) L-circle dot. Combining the H alpha and far-IR luminosities, we derive median star formation rates (SFRs) of SFRH alpha, FIR = 32 +/- 5 M-circle dot yr(-1) and H alpha extinctions of A(H alpha) = 1.0 +/- 0.2 mag. Perhaps surprisingly, little difference is seen in typical HiZELS extinction levels compared to local star-forming galaxies. We confirm previous empirical stellar mass (M-*) to A(H alpha) relations and the little or no evolution up to z = 1.47. For HiZELS galaxies (or similar samples) we provide an empirical parametrization of the SFR as a function of rest-frame (u - z) colours and 3.6-mu m photometry - a useful proxy to aid in the absence of far-IR detections in high-z galaxies. We find that the observed H alpha luminosity is a dominant SFR tracer when rest-frame (u - z) colours are less than or similar to 0.9 mag or when Spitzer-3.6-mu m photometry is fainter than 22 mag (Vega) or when stellar masses are lower than 10(9.7) M-circle dot. We do not find any correlation between the [O ii]/H alpha and far-IR luminosity, suggesting that this emission line ratio does not trace the extinction of the most obscured star-forming regions, especially in massive galaxies where these dominate. The luminosity-limited HiZELS sample tends to lie above of the so-called main sequence for star-forming galaxies, especially at low stellar masses, indicating high star formation efficiencies in these galaxies. This work has implications for SFR indicators and suggests that obscured star formation is linked to the assembly of stellar mass, with deeper potential wells in massive galaxies providing dense, heavily obscured environments in which stars can form rapidly.
NUCLEAR ACTIVITY IS MORE PREVALENT IN STAR-FORMING GALAXIES
(2013) Rosario, D. J.; Santini, P.; Lutz, D.; Netzer, H.; Bauer, F. E.; Berta, S.; Magnelli, B.; Popesso, P.; Alexander, D. M.; Brandt, W. N.; Genzel, R.; Maiolino, R.; Mullaney, J. R.; Nordon, R.; Saintonge, A.; Tacconi, L.; Wuyts, S.
We explore the question of whether low and moderate luminosity active galactic nuclei (AGNs) are preferentially found in galaxies that are undergoing a transition from active star formation (SF) to quiescence. This notion has been suggested by studies of the UV-optical colors of AGN hosts, which find them to be common among galaxies in the so-called Green Valley, a region of galaxy color space believed to be composed mostly of galaxies undergoing SF quenching. Combining the deepest current X-ray and Herschel/PACS far-infrared (FIR) observations of the two Chandra Deep Fields with redshifts, stellar masses, and rest-frame photometry derived from the extensive and uniform multi-wavelength data in these fields, we compare the rest-frame U - V color distributions and star formation rate distributions of AGNs and carefully constructed samples of inactive control galaxies. The UV-to-optical colors of AGNs are consistent with equally massive inactive galaxies at redshifts out to z similar to 2, but we show that such colors are poor tracers of SF. While the FIR distributions of both star-forming AGNs and star-forming inactive galaxies are statistically similar, we show that AGNs are preferentially found in star-forming host galaxies, or, in other words, AGNs are less likely to be found in weakly star-forming or quenched galaxies. We postulate that, among X-ray-selected AGNs of low and moderate accretion luminosities, the supply of cold gas primarily determines the accretion rate distribution of the nuclear black holes.
The ALMA Spectroscopic Survey in the HUDF : Deep 1.2 mm Continuum Number Counts
(2020) Gonzalez Lopez, J.; Novak, M.; Decarli, R.; Walter, F.; Aravena, M.; Carilli, C.; Boogaard, L.; Popping, G.; Weiss, A.; Bauer, Franz Erik; Assef, R. J.; Bouwens, R.; Cortes, P. C.; Cox, P.; Daddi, E.; Cunha, E.; Diaz Santos, T.; Ivison, R.; Magnelli, B.; Riechers, D.; Smail, I.; van der Werf, P.; Wagg, J.
The ALMA Spectroscopic Survey in the HUDF : The Cosmic Dust and Gas Mass Densities in Galaxies up to z ∼ 3
(2020) Magnelli, B.; Boogaard, L.; Decarli, R.; Gonzalez Lopez, J.; Novak, M.; Popping, G.; Smail, I.; Walter, F.; Aravena, M.; Bauer, Franz Erik; Assef, R. J.; Bertoldi, F.; Carilli, C.; Cortes, P. C.; da Cunha, E.; Daddi, E.; Diaz Santos, T.; Inami, H.; Ivison, R. J.; Le Fevre, O.; Oesch, P.; Riechers, D.; Rix, H. W.; Sargent, M. T.; van der Werf, P.; Wagg, J.; Weiss, A.
The evolution of the Baryons associated with Galaxies averaged over cosmic time and space
(2020) Walter, F.; Carilli, C.; Neeleman, M.; Decarli, R.; Popping, G.; Somerville, R. S.; Aravena, M.; Bertoldi, F.; Boogaard, L.; Bauer, Franz Erik; Cox, P.; Cunha, E. da; Magnelli, B.; Obreschkow, D.; Riechers, D.; Rix, H. W.; Smail, I.; Weiss, A.; Assef, R. J.; Bouwens, R.; Contini, T.; Cortés, P. C.; Daddi, E.; Díaz Santos, T.; González López, Jorge; Hennawi, J.; Hodge, J. A.; Inami, H.; Ivison, R.; Oesch, P.; Sargent, M.; Werf, P. van der; Wagg, J.; Yung, L. Y. A.
The hidden side of cosmic star formation at z > 3 Bridging optically dark and Lyman-break galaxies with GOODS-ALMA
(2023) Xiao, M-Y.; Elbaz, D.; Gomez-Guijarro, C.; Leroy, L.; Bing, L-J.; Daddi, E.; Magnelli, B.; Franco, M.; Zhou, L.; Dickinson, M.; Wang, T.; Rujopakarn, W.; Magdis, G. E.; Treister, Ezequiel; Inami, H.; Demarco, R.; Sargent, M. T.; Shu, X.; Kartaltepe, J. S.; Alexander, D. M.; Bethermin, M.; Bournaud, F.; Ciesla, L.; Ferguson, H. C.; Finkelstein, S. L.; Giavalisco, M.; Gu, Q-S.; Iono, D.; Juneau, S.; Lagache, G.; Leiton, R.; Messias, H.; Motohara, K.; Mullaney, J.; Nagar, N.; Pannella, M.; Papovich, C.; Pope, A.; Schreiber, C.; Silverman, J.
Our current understanding of the cosmic star formation history at z > 3 is primarily based on UV-selected galaxies (Lyman-break galaxies, i.e., LBGs). Recent studies of H-dropouts (HST-dark galaxies) have revealed that we may be missing a large proportion of star formation that is taking place in massive galaxies at z > 3. In this work, we extend the H-dropout criterion to lower masses to select optically dark or faint galaxies (OFGs) at high redshifts in order to complete the census between LBGs and H-dropouts. Our criterion (H > 26.5 mag & [4.5] < 25 mag) combined with a de-blending technique is designed to select not only extremely dust-obscured massive galaxies but also normal star-forming galaxies (typically E(B - V) > 0.4) with lower stellar masses at high redshifts. In addition, with this criterion, our sample is not contaminated by massive passive or old galaxies. In total, we identified 27 OFGs at (Zphot) > 3 (with a median of z(med) = 4.1) in the GOODS-ALMA field, covering a wide distribution of stellar masses with log(M-star/M-circle dot) = 9.4-11.1 (with a median of log(M-star med/M-circle dot) = 10.3). We find that up to 75% of the OFGs with log(M-star/M-circle dot) = 9.5-10.5 were neglected by previous LBGs and H-dropout selection techniques. After performing an optical-to-millimeter stacking analysis of the OFGs, we find that rather than being limited to a rare population of extreme starbursts, these OFGs represent a normal population of dusty star-forming galaxies at z > 3. The OFGs exhibit shorter gas depletion timescales, slightly lower gas fractions, and lower dust temperatures than the scaling relation of typical star-forming galaxies. Additionally, the total star formation rate (SFRtot = SFRIR + SFRUV) of the stacked OFGs is much higher than the SFRUVcorr (SFRUV corrected for dust extinction), with an average SFRtot/SFRUVcorr = 8 +/- 1, which lies above (similar to 0.3 dex) the 16-84th percentile range of typical star-forming galaxies at 3 <= z <= 6. All of the above suggests the presence of hidden dust regions in the OFGs that absorb all UV photons, which cannot be reproduced with dust extinction corrections. The effective radius of the average dust size measured by a circular Gaussian model fit in the uv plane is R-e(1.13 mm) = 1.01 +/- 0.05 kpc. After excluding the five LBGs in the OFG sample, we investigated their contributions to the cosmic star formation rate density (SFRD). We found that the SFRD at z > 3 contributed by massive OFGs (log(M-star/M-circle dot) > 10.3) is at least two orders of magnitude higher than the one contributed by equivalently massive LBGs. Finally, we calculated the combined contribution of OFGs and LBGs to the cosmic SFRD at z = 4-5 to be 4 x 10(-2) M-circle dot yr(-1) Mpc(-3), which is about 0.15 dex (43%) higher than the SFRD derived from UV-selected samples alone at the same redshift. This value could be even larger, as our calculations were performed in a very conservative way.
The hidden side of cosmic star formation at z > 3 Bridging optically dark and Lyman-break galaxies with GOODS-ALMA
(Wiley, 2023) Xiao, M-Y.; Elbaz, D.; Gomez-Guijarro, C.; Leroy, L.; Bing, L-J.; Daddi, E.; Magnelli, B.; Franco, M.; Zhou, L.; Dickinson, M.; Wang, T.; Rujopakarn, W.; Magdis, G. E.; Treister, Ezequiel; Inami, H.; Demarco, R.; Sargent, M. T.; Shu, X.; Kartaltepe, J. S.; Alexander, D. M.; Bethermin, M.; Bournaud, F.; Ciesla, L.; Ferguson, H. C.; Finkelstein, S. L.; Giavalisco, M.; Gu, Q-S.; Iono, D.; Juneau, S.; Lagache, G.; Leiton, R.; Messias, H.; Motohara, K.; Mullaney, J.; Nagar, N.; Pannella, M.; Papovich, C.; Pope, A.; Schreiber, C.; Silverman, J.
Our current understanding of the cosmic star formation history at z > 3 is primarily based on UV-selected galaxies (Lyman-break galaxies, i.e., LBGs). Recent studies of H-dropouts (HST-dark galaxies) have revealed that we may be missing a large proportion of star formation that is taking place in massive galaxies at z > 3. In this work, we extend the H-dropout criterion to lower masses to select optically dark or faint galaxies (OFGs) at high redshifts in order to complete the census between LBGs and H-dropouts. Our criterion (H > 26.5 mag & [4.5] < 25 mag) combined with a de-blending technique is designed to select not only extremely dust-obscured massive galaxies but also normal star-forming galaxies (typically E(B - V) > 0.4) with lower stellar masses at high redshifts. In addition, with this criterion, our sample is not contaminated by massive passive or old galaxies. In total, we identified 27 OFGs at (Zphot) > 3 (with a median of z(med) = 4.1) in the GOODS-ALMA field, covering a wide distribution of stellar masses with log(M-star/M-circle dot) = 9.4-11.1 (with a median of log(M-star med/M-circle dot) = 10.3). We find that up to 75% of the OFGs with log(M-star/M-circle dot) = 9.5-10.5 were neglected by previous LBGs and H-dropout selection techniques. After performing an optical-to-millimeter stacking analysis of the OFGs, we find that rather than being limited to a rare population of extreme starbursts, these OFGs represent a normal population of dusty star-forming galaxies at z > 3. The OFGs exhibit shorter gas depletion timescales, slightly lower gas fractions, and lower dust temperatures than the scaling relation of typical star-forming galaxies. Additionally, the total star formation rate (SFRtot = SFRIR + SFRUV) of the stacked OFGs is much higher than the SFRUVcorr (SFRUV corrected for dust extinction), with an average SFRtot/SFRUVcorr = 8 +/- 1, which lies above (similar to 0.3 dex) the 16-84th percentile range of typical star-forming galaxies at 3 <= z <= 6. All of the above suggests the presence of hidden dust regions in the OFGs that absorb all UV photons, which cannot be reproduced with dust extinction corrections. The effective radius of the average dust size measured by a circular Gaussian model fit in the uv plane is R-e(1.13 mm) = 1.01 +/- 0.05 kpc. After excluding the five LBGs in the OFG sample, we investigated their contributions to the cosmic star formation rate density (SFRD). We found that the SFRD at z > 3 contributed by massive OFGs (log(M-star/M-circle dot) > 10.3) is at least two orders of magnitude higher than the one contributed by equivalently massive LBGs. Finally, we calculated the combined contribution of OFGs and LBGs to the cosmic SFRD at z = 4-5 to be 4 x 10(-2) M-circle dot yr(-1) Mpc(-3), which is about 0.15 dex (43%) higher than the SFRD derived from UV-selected samples alone at the same redshift. This value could be even larger, as our calculations were performed in a very conservative way.
The incidence of obscuration in active galactic nuclei.
(2014) Merloni, A.; Treister, Ezequiel; Bongiorno, A.; Brusa, Marcella; Iwasawa, K.; Mainieri, V.; Magnelli, B.; Salvato, M.; Berta, S.; Cappelluti N; Comastri, A.
The mean star formation rate of X-ray selected active galaxies and its evolution from z ~ 2.5: results from PEP-Herschel
(2012) Rosario, D. J.; Santini, P.; Lutz, D.; Shao, L.; Maiolino, R.; Alexander, D. M.; Altieri, B.; Andreani, P.; Aussel, H.; Bauer, F. E.; Berta, S.; Bongiovanni, A.; Brandt, W. N.; Brusa, M.; Cepa, J.; Cimatti, A.; Cox, T. J.; Daddi, E.; Elbaz, D.; Fontana, A.; Schreiber, N. M. Foerster; Genzel, R.; Grazian, A.; Le Floch, E.; Magnelli, B.; Mainieri, V.; Netzer, H.; Nordon, R.; Garcia, I. Perez; Poglitsch, A.; Popesso, P.; Pozzi, F.; Riguccini, L.; Rodighiero, G.; Salvato, M.; Sanchez-Portal, M.; Sturm, E.; Tacconi, L. J.; Valtchanov, I.; Wuyts, S.
We study relationships between star-formation rate (SFR) and the accretion luminosity and nuclear obscuration of X-ray selected active galactic nuclei (AGNs) using a combination of deep far-infrared (FIR) and X-ray data in three key extragalactic survey fields (GOODS-South, GOODS-North and COSMOS), as part of the PACS Evolutionary Probe (PEP) program. The use of three fields with differing areas and depths enables us to explore trends between the global FIR luminosity of the AGN hosts and the luminosity of the active nucleus across 4.5 orders of magnitude in AGN luminosity (L-AGN) and spanning redshifts from the Local Universe to z = 2.5. Using imaging from the Herschel/PACS instrument in 2-3 bands, we combine FIR detections and stacks of undetected objects to arrive at mean fluxes for subsamples in bins of redshift and X-ray luminosity. We constrain the importance of AGN-heated dust emission in the FIR and confirm that the majority of the FIR emission of AGNs is produced by cold dust heated by star-formation in their host galaxies.

Browsing by Author "Magnelli, B."

Results Per Page

Sort Options