We present results for the first three years of OzDES, a six-year program to obtain redshifts for objects in the Dark Energy Survey (DES) supernova fields using the 2dF fibre positioner and AAOmega spectrograph on the Anglo-Australian Telescope. OzDES is a multi-object spectroscopic survey targeting multiple types of targets at multiple epochs over a multi-year baseline, and is one of the first multi-object spectroscopic surveys to dynamically include transients into the target list soon after their discovery. At the end of three years, OzDES has spectroscopically confirmed almost 100 supernovae, and has measured redshifts for 17,000 objects, including the redshifts of 2,566 supernova hosts. We examine how our ability to measure redshifts for targets of various types depends on signal-to-noise, magnitude, and exposure time, finding that our redshift success rate increases significantly at a signal-to-noise of 2 to 3 per 1-Angstrom bin. We also find that the change in signal-to-noise with exposure time closely matches the Poisson limit for stacked exposures as long as 10 hours. We use these results to predict the redshift yield of the full OzDES survey, as well as the potential yields of future surveys on other facilities such as 4MOST, PFS, and MSE. This work marks the first OzDES data release, comprising 14,693 redshifts. OzDES is on target to obtain over 30,000 redshifts over the six-year duration of the survey, including a yield of approximately 5,700 supernova host-galaxy redshifts.
We present the construction and describe the properties of the Padova-Millennium Galaxy and Group Catalogue (PM2GC), a galaxy catalogue representative of the general field population in the local Universe. We characterize galaxy environments by identifying galaxy groups at 0.04<=z<=0.1 with a Friends-of-Friends (FoF) algorithm using a complete sample of 3210 galaxies brighter than M_B_=-18.7 taken from the Millennium Galaxy Catalogue (MGC, Liske et al., 2003, Cat. VII/240), a 38deg^2^ image photometric and spectroscopic equatorial survey. We identified 176 groups with at least three members, comprising in total 1057 galaxies and representing ~43 per cent of the general field population in that redshift range.
The characteristics of the starburst galaxies from the Pico dos Dias Survey (PDS, Coziol et al., 1998ApJS..119..239C) are compared with those of the nearby ultraviolet (UV) bright Markarian starburst galaxies, having the same limit in redshift (v_h_<7500km/s) and absolute B magnitude (M_B_<18). An important difference is found: the Markarian galaxies are generally undetected at 12 and 25um in IRAS. This is consistent with the UV excess shown by these galaxies and suggests that the youngest star-forming regions dominating these galaxies are relatively free of dust.
We derive peculiar velocities for the 6dF Galaxy Survey (6dFGS) and describe the velocity field of the nearby (z<0.055) Southern hemisphere. The survey comprises 8885 galaxies for which we have previously reported Fundamental Plane data. We obtain peculiar velocity probability distributions for the redshift-space positions of each of these galaxies using a Bayesian approach. Accounting for selection bias, we find that the logarithmic distance uncertainty is 0.11 dex, corresponding to 26 per cent in linear distance. We use adaptive kernel smoothing to map the observed 6dFGS velocity field out to cz~16000km/s, and compare this to the predicted velocity fields from the PSCz Survey and the 2MASS Redshift Survey. We find a better fit to the PSCz prediction, although the reduced {chi}^2^ for the whole sample is approximately unity for both comparisons. This means that, within the observational uncertainties due to redshift-independent distance errors, observed galaxy velocities and those predicted by the linear approximation from the density field agree. However, we find peculiar velocities that are systematically more positive than model predictions in the direction of the Shapley and Vela superclusters, and systematically more negative than model predictions in the direction of the Pisces-Cetus Supercluster, suggesting contributions from volumes not covered by the models.
Star formation rates (SFRs) are crucial to constrain theories of galaxy formation and evolution. SFRs are usually estimated via spectroscopic observations requiring large amounts of telescope time. We explore an alternative approach based on the photometric estimation of global SFRs for large samples of galaxies, by using methods such as automatic parameter space optimisation, and supervised machine learning models. We demonstrate that, with such approach, accurate multiband photometry allows to estimate reliable SFRs. We also investigate how the use of photometric rather than spectroscopic redshifts, affects the accuracy of derived global SFRs. Finally, we provide a publicly available catalogue of SFRs for more than 27 million galaxies extracted from the Sloan Digital Sky Survey Data Release 7. The catalogue will be made available through the Vizier facility.
Photometry and Spectroscopy of Elliptical Galaxies
Short Name:
VII/176A
Date:
21 Oct 2021
Publisher:
CDS
Description:
Photometric and spectroscopic data are presented for a survey of the nearest and brightest elliptical galaxies. Distances, velocities relative to the cosmic rest frame, and residual velocities relative to a velocity-flow model are calculated for individual galaxies and groups. Information is provided on the selection and completeness of the target and observed samples. Both samples appear to be noticeably deeper in the north than in the south. A new diameter system for ellipticals is described that is easy to measure on survey prints and is a useful indicator of B_T_ magnitude.
We present the results of Thuan & Gunn r CCD imaging observations of the Universidad Complutense de Madrid (UCM) sample of emission-line galaxies (ELGs), selected by the presence of H{alpha} emission in low-resolution objective prism spectra. In this work we characterize photometrically and morphologically a total of 212 objects from the UCM survey. This Paper presents the observations and basic reductions, and lists a set of photometric parameters calculated for each UCM object. In addition, for the first time in a ELGs sample, we have determined the morphological classification of the objects using simultaneously five different criteria.
We present Johnson B CCD photometry for the whole sample of galaxies of the Universidad Complutense de Madrid (UCM) Survey Lists I and II (Cat. <J/ApJS/95/387> and <J/ApJS/105/343>). They constitute a well-defined and complete sample of galaxies in the Local Universe with active star formation. The data refer to 191 S0 to Irr galaxies at an averaged redshift of 0.027, and complement the already published Gunn r, J and K photometries. (B-r) colours are also computed.
The catalog contains 510 extragalactic radio sources, and covers all polarization measurements from 1965 to the middle of 1974 and a few other radio and optical data for these sources. The typical observation error was in the range of 1-2 percent in 1965 and 0.5-1 percent in 1974. The selection criterion for sources was that polarization data should be available at least at three wavelengths for each source. This reduced the sample to 510 sources. The catalog includes observational data: classifications, Cambridge numbers, coordinates, degrees of polarization at various wavelengths, polarization angles at each wavelength, largest angular diameters, position angles, and redshifts. The catalog also includes derived data: rotation measures, linear source diameters, polarization angles at wavelength 0 cm, differences between position angle and polarization angle at 0 cm, spectral indices between each pair of successive wavelengths observed, and polarization indices between each pair of successive wavelengths observed.
We present finding charts and J2000 positions accurate to ~1" for the 528 high-redshift (z>1), luminous (M_v_<-25.5) quasars investigated in the Hubble Space Telescope Snapshot Survey. The information was produced with the Space Telescope Science Institute's Astrometric Support Program.
