Browsing by Author "Rosario, D. J."
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- ItemEnhanced 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.
- ItemNUCLEAR 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.
- ItemThe host galaxies of X- ray selected active galactic nuclei to z=2.5 : Structure star formation and their relationships from CANDELS and Herschel/PACS(2015) Rosario, D. J.; McIntosh, D. H.; van der Wel, A.; Kartaltepe, J.; Lang, P.; Santini, P.; Wuyts, S.; Lutz, D.; Rafelsk, M.; Bauer, Franz Erik
- ItemThe 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.
- ItemThe nature of sub-millimetre galaxies II: an ALMA comparison of SMG dust heating mechanisms(2022) Ansarinejad, B.; Shanks, T.; Bielby, R. M.; Metcalfe, N.; Infante, L.; Murphy, D. N. A.; Rosario, D. J.; Stach, S. M.We compare the contribution of active galactic nuclei (AGNs) and star formation towards dust heating in sub-mm galaxies (SMGs). We have used ALMA at 0.1-arcsec resolution to image a complete flux-limited sample of seven sub-mm sources previously shown to have spectral energy distributions that were as well-fitted by obscured AGN as star-forming galaxy templates. Indeed, two sub-mm sources were known to be quasars from their absorbed X-ray emission. We find the sub-mm sizes of all SMGs to be small (approximate to 1-2 kpc) and generally similar to 3 times smaller than any host detected in the near-infrared (NIR). In all cases, the five SMGs are comparable in sub-mm size to the two known quasars and four z approximate to 6 quasars, also observed with ALMA. We detect no evidence of diffuse spiral arms in this complete sample. We then convert the far-infrared (FIR) luminosities to star formation rate (SFR) surface densities and find that the SMGs occupy the same range as the known quasars in our sample. We conclude that in terms of sub-mm size, extent relative to host and SFR density as well as luminosity and mid-IR (MIR) colour, there is little distinction between the SMGs and sub-mm bright quasars. Finally, we present preliminary evidence that SMGs with higher MIR luminosities and sub-mm loud quasars tend to have dust components that range to hotter temperatures than their less luminous SMG counterparts. In light of these results, we continue to suggest that luminous SMGs may host dust-absorbed quasars that may simultaneously dominate the FIR and hard X-ray backgrounds.
- ItemThe nature of sub-millimetre galaxies II: an ALMA comparison of SMG dust heating mechanisms(2022) Ansarinejad, B.; Shanks, T.; Bielby, R. M.; Metcalfe, N.; Infante, L.; Murphy, D. N. A.; Rosario, D. J.; Stach, S. M.We compare the contribution of active galactic nuclei (AGNs) and star formation towards dust heating in sub-mm galaxies (SMGs). We have used ALMA at 0.1-arcsec resolution to image a complete flux-limited sample of seven sub-mm sources previously shown to have spectral energy distributions that were as well-fitted by obscured AGN as star-forming galaxy templates. Indeed, two sub-mm sources were known to be quasars from their absorbed X-ray emission. We find the sub-mm sizes of all SMGs to be small (approximate to 1-2 kpc) and generally similar to 3 times smaller than any host detected in the near-infrared (NIR). In all cases, the five SMGs are comparable in sub-mm size to the two known quasars and four z approximate to 6 quasars, also observed with ALMA. We detect no evidence of diffuse spiral arms in this complete sample. We then convert the far-infrared (FIR) luminosities to star formation rate (SFR) surface densities and find that the SMGs occupy the same range as the known quasars in our sample. We conclude that in terms of sub-mm size, extent relative to host and SFR density as well as luminosity and mid-IR (MIR) colour, there is little distinction between the SMGs and sub-mm bright quasars. Finally, we present preliminary evidence that SMGs with higher MIR luminosities and sub-mm loud quasars tend to have dust components that range to hotter temperatures than their less luminous SMG counterparts. In light of these results, we continue to suggest that luminous SMGs may host dust-absorbed quasars that may simultaneously dominate the FIR and hard X-ray backgrounds.
- ItemThe VANDELS ESO public spectroscopic survey: Final data release of 2087 spectra and spectroscopic measurements(2021) Garilli, B.; McLure, R.; Pentericci, L.; Franzetti, P.; Gargiulo, A.; Carnall, A.; Cucciati, O.; Iovino, A.; Amorin, R.; Bolzonella, M.; Bongiorno, A.; Castellano, M.; Cimatti, A.; Cirasuolo, M.; Cullen, F.; Dunlop, J.; Elbaz, D.; Finkelstein, S.; Fontana, A.; Fontanot, F.; Fumana, M.; Guaita, L.; Hartley, W.; Jarvis, M.; Juneau, S.; Maccagni, D.; McLeod, D.; Nandra, K.; Pompei, E.; Pozzetti, L.; Scodeggio, M.; Talia, M.; Calabro, A.; Cresci, G.; Fynbo, J. P. U.; Hathi, N. P.; Hibon, P.; Koekemoer, A. M.; Magliocchetti, M.; Salvato, M.; Vietri, G.; Zamorani, G.; Almaini, O.; Balestra, I.; Bardelli, S.; Begley, R.; Brammer, G.; Bell, E. F.; Bowler, R. A. A.; Brusa, M.; Buitrago, F.; Caputi, C.; Cassata, P.; Charlot, S.; Citro, A.; Cristiani, S.; Curtis-Lake, E.; Dickinson, M.; Fazio, G.; Ferguson, H. C.; Fiore, F.; Franco, M.; Georgakakis, A.; Giavalisco, M.; Grazian, A.; Hamadouche, M.; Jung, I.; Kim, S.; Khusanova, Y.; Le Fevre, O.; Longhetti, M.; Lotz, J.; Mannucci, F.; Maltby, D.; Matsuoka, K.; Mendez-Hernandez, H.; Mendez-Abreu, J.; Mignoli, M.; Moresco, M.; Nonino, M.; Pannella, M.; Papovich, C.; Popesso, P.; Roberts-Borsani, G.; Rosario, D. J.; Saldana-Lopez, A.; Santini, P.; Saxena, A.; Schaerer, D.; Schreiber, C.; Stark, D.; Tasca, L. A. M.; Thomas, R.; Vanzella, E.; Wild, V.; Williams, C.; Zucca, E.VANDELS is an ESO Public Spectroscopic Survey designed to build a sample of high-signal-to-noise ratio, medium-resolution spectra of galaxies at redshifts between 1 and 6.5. Here we present the final Public Data Release of the VANDELS Survey, comprising 2087 redshift measurements. We provide a detailed description of sample selection, observations, and data reduction procedures. The final catalogue reaches a target selection completeness of 40% at i(AB)=25. The high signal-to-noise ratio of the spectra (above 7 in 80% of the spectra) and the dispersion of 2.5 angstrom allowed us to measure redshifts with high precision, the redshift measurement success rate reaching almost 100%. Together with the redshift catalogue and the reduced spectra, we also provide optical mid-infrared photometry and physical parameters derived through fitting the spectral energy distribution. The observed galaxy sample comprises both passive and star forming galaxies covering a stellar mass range of 8.3 < Log(M-*/M-circle dot) < 11.7.