The MOSDEF survey: a new view of a remarkable z = 1.89 merger

Large scale structure and cosmolog

Reconciling the results of the z ~ 2 MOSDEF and KBSS-MOSFIRE Surveys

Large scale structure and cosmolog

Herschel/PACS OH Spectroscopy of Seyfert, LINER, and Starburst Galaxies

We investigated the 65, 71, 79, 84, 119, and 163 μm OH doublets of 178 local (0 < z < 0.35) galaxies. They were observed using the Herschel/Photoconductor Array Camera and Spectrometer, including Seyfert galaxies, low-ionization nuclear emission-line regions, and star-forming galaxies. We observe these doublets exclusively in absorption (OH71), primarily in absorption (OH65, OH84), mostly in emission (OH79), only in emission (OH163), and an approximately even mix of the both (OH119). In 19 galaxies we find P Cygni or reverse P Cygni line profiles in the OH doublets. We use several galaxy observables to probe spectral classification, brightness of a central active galactic nucleus (AGN)/starburst component, and radiation field strength. We find that OH79, OH119, and OH163 are more likely to display strong emission for bright, unobscured AGNs. For less luminous, obscured AGNs and nonactive galaxies, we find populations of strong absorption (OH119), weaker emission (OH163), and a mix of weak emission and weak absorption (OH79). For OH65, OH71, and OH84, we do not find significant correlations with the observables listed above. For OH79 and OH119, we find relationships with both the 9.7 μm silicate feature and Balmer decrement dust extinction tracers in which more dust leads to weaker emission/stronger absorption. The origin of emission for the observed OH doublets, whether from collisional excitation or from radiative pumping by infrared photons, is discussed.With funding from the Spanish government through the "María de Maeztu Unit of Excellence" accreditation (MDM-2017-0737

The MOSDEF survey: towards a complete census of the z ~ 2.3 star-forming galaxy population

Large scale structure and cosmolog

Reconciling the results of the z ∼2 MOSDEF and KBSS-MOSFIRE Surveys

The combination of the MOSDEF and KBSS-MOSFIRE surveys represents the largest joint investment of Keck/MOSFIRE time to date, with ∼3000 galaxies at 1.4 z 3.8, roughly half of which are at z ∼2. MOSDEF is photometric- and spectroscopic-redshift selected with a rest-optical magnitude limit, while KBSS-MOSFIRE is primarily selected based on rest-UV colours and a rest-UV magnitude limit. Analysing both surveys in a uniform manner with consistent spectral-energy- distribution (SED) models, we find that the MOSDEF z ∼2 targeted sample has higher median M ∗and redder rest U −V colour than the KBSS-MOSFIRE z ∼2 targeted sample, and smaller median SED-based SFR and sSFR (SFR(SED) and sSFR(SED)). Specifically, MOSDEF tar geted a larger population of red galaxies with U −V and V −J >1.25, while KBSS-MOSFIRE contains more young galaxies with intense star formation. Despite these differences in the z ∼2 targeted samples, the subsets of the surveys with multiple emission lines detected and analysed in previous work are much more similar. All median host-galaxy properties with the exception of stellar population age -i.e. M ∗, SFR(SED), sSFR(SED), A V , and UVJ colours -agree within the uncertainties. Additionally, when uniform emission-line fitting and stellar Balmer absorption correction techniques are applied, there is no significant offset between both samples in the [O III ] λ5008/H βversus [N II ] λ6585/H αdiagnostic diagram, in contrast to previously reported discrepancies. We can now combine the MOSDEF and KBSS-MOSFIRE surv e ys to form the largest z ∼2 sample with moderate-resolution rest-optical spectra and construct the fundamental scaling relations of star-forming galaxies during this important epoch. © 2022 The Author(s)Immediate accessThis item from the UA Faculty Publications collection is made available by the University of Arizona with support from the University of Arizona Libraries. If you have questions, please contact us at [email protected]