- ID:
- ivo://CDS.VizieR/J/MNRAS/436/2915
- Title:
- Polarization of bright AT20G sources
- Short Name:
- J/MNRAS/436/2915
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present polarization data for 180 extragalactic sources extracted from the Australia Telescope 20GHz (AT20G) survey catalogue and observed with the Australia Telescope Compact Array during a dedicated, high sensitivity run ({sigma}_P_~1mJy). For the sake of completeness, we extracted the polarization information for seven extended sources from the 9yr Wilkinson Microwave Anisotropy Probe co-added maps at 23GHz. The full sample of 187 sources constitutes a =~99% complete sample of extragalactic sources brighter than S_20GHz_=500mJy at the selection epoch with declination {delta}<-30{deg}. The sample has a 91.4% detection rate in polarization at ~20GHz (94 percent if considering the subsample of point-like sources). We have measurements also at 4.8 and 8.6GHz within ~1 month of the 20GHz observations for 172 sources to reconstruct the spectral properties of the sample in total intensity and in polarization: 143 of them have a polarization detection at all three frequencies. We find that there is no statistically significant evidence of a relationship either between the fraction of polarization and frequency or between the fraction of polarization and the total intensity flux density. This indicates that Faraday depolarization is not very important above 4.8GHz and that the magnetic field is not substantially more ordered in the regions dominating the emission at higher frequencies (up to 20GHz). We estimate the distribution of the polarization fraction and the polarized flux density source counts at ~20GHz.
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- ID:
- ivo://CDS.VizieR/VII/6
- Title:
- Polarization of Extragalactic Radio Sources
- Short Name:
- VII/6
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- 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.
2843. Polarized DRAO sources
- ID:
- ivo://CDS.VizieR/J/ApJ/733/69
- Title:
- Polarized DRAO sources
- Short Name:
- J/ApJ/733/69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Dominion Radio Astrophysical Observatory Deep Field polarization study has been matched with the Spitzer Wide-Area Infrared Extragalactic Survey of the European Large Area Infrared Space Observatory Survey North 1 field. We have used Very Large Array observations with a total intensity rms of 87uJy/beam to match SWIRE counterparts to the radio sources. Infrared color analysis of our radio sample shows that the majority of polarized sources are elliptical galaxies with an embedded active galactic nucleus. Using available redshift catalogs, we found 429 radio sources of which 69 are polarized with redshifts in the range of 0.04<z<3.2. We find no correlation between redshift and percentage polarization for our sample. However, for polarized radio sources, we find a weak correlation between increasing percentage polarization and decreasing luminosity.
- ID:
- ivo://CDS.VizieR/J/A+A/549/A47
- Title:
- Position and photometry of stars in SDIG
- Short Name:
- J/A+A/549/A47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the resolved stellar populations and derive the star formation history of the Sculptor dwarf irregular galaxy (SDIG), a gas-rich dwarf galaxy member of the NGC 7793 subgroup in the Sculptor group of galaxies. We constructed a colour - magnitude diagram (CMD) using archival observations from the Hubble Space Telescope/Advanced Camera for Surveys in order to examine the stellar content of SDIG, as well as the spatial distribution of stars selected within different stellar evolutionary phases. We derived the star formation history of SDIG using a maximum-likelihood fit to the CMD.
- ID:
- ivo://CDS.VizieR/J/ApJ/793/135
- Title:
- Positions and distances of RR Lyrae stars
- Short Name:
- J/ApJ/793/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Almost every known low-luminosity Milky Way dwarf spheroidal (dSph) satellite galaxy contains at least one RR Lyrae star. Assuming that a fraction of distant (60<d_helio_<100 kpc) Galactic halo RR Lyrae stars are members of yet to be discovered low-luminosity dSph galaxies, we perform a guided search for these low-luminosity dSph galaxies. In order to detect the presence of dSph galaxies, we combine stars selected from more than 123 sightlines centered on RR Lyrae stars identified by the Palomar Transient Factory. We find that this method is sensitive enough to detect the presence of Segue 1-like galaxies (M_V_=-1.5_-0.8_^+0.6^, r_h_=30 pc) even if only ~20 sightlines were occupied by such dSph galaxies. Yet, when our method is applied to the Sloan Digital Sky Survey Data Release 10 imaging catalog, no signal is detected. An application of our method to sightlines occupied by pairs of close (<200 pc) horizontal branch stars, also did not yield a detection. Thus, we place upper limits on the number of low-luminosity dSph galaxies with half-light radii from 30 pc to 120 pc, and in the probed volume of the halo. Stronger constraints on the luminosity function may be obtained by applying our method to sightlines centered on RR Lyrae stars selected from the Pan-STARRS1 survey, and eventually, from the Large Synoptic Survey Telescope. In Appendix A, we present spectroscopic observations of an RRab star in the Bootes 3 dSph and a light curve of an RRab star near the Bootes 2 dSph.
- ID:
- ivo://CDS.VizieR/J/ApJ/633/871
- Title:
- Positions and photometry of HII knots in M51
- Short Name:
- J/ApJ/633/871
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Far-ultraviolet to far-infrared images of the nearby galaxy NGC 5194 (M51a), from a combination of space-based (Spitzer, GALEX, and Hubble Space Telescope) and ground-based data, are used to investigate local and global star formation and the impact of dust extinction. The Spitzer data provide unprecedented spatial detail in the infrared, down to sizes 500 pc at the distance of NGC 5194. The multiwavelength set is used to trace the relatively young stellar populations, the ionized gas, and the dust absorption and emission in HII-emitting knots, over 3 orders of magnitude in wavelength range.
- ID:
- ivo://CDS.VizieR/J/A+A/374/861
- Title:
- Positions of giant radio galaxies
- Short Name:
- J/A+A/374/861
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In tablea1.dat, we present the WENSS selected candidate GRGs after removing sources identified as non-GRGs on basis of optical data. In tablea2.dat, we present the log of the spectroscopic observations of GRG andidates in our sample. In tablea3.dat, we present properties of the radio cores and the optical identifications of the spectroscopically observed giant radio sources, and of the confirmed giant sources B1144+352, B1245+676 and B1310+451. We provide the name of the radio source in IAU notation, the observation used to determine the radio core position and its flux density and the radio core position in right ascension and declination, respectively, in B1950.0 coordinates. The radio positions have been obtained by fitting a Gaussian in the radio map. We further provide the integrated flux density at 1.4GHz of the radio core, the position of the optical identification in right ascension and declination, respectively, in B1950.0 coordinates, obtained from fitting a Gaussian in the available optical image and the magnitude of the identification in the red (POSS-E) band of the Palomar survey. The magnitudes for sources weaker than 15.0 have been obtained from the APM catalogue and are estimated to be accurate to 0.5 mag. For brighter sources, we have measured the magnitudes directly from the digitized POSS-I frames using the photometric calibration for stars available from the STScI WWW-pages and through the getimage-2.0 plate retrieval software. Typical uncertainties in these values are estimated to be large, at least 1mag. In tablea4.dat, further radio properties of the sources in tablea3.dat. We present the integrated flux density of the source at 325MHz from the Westerbork Northern Sky Survey (WENSS) (unless stated otherwise), the integrated flux density at 1400MHz from the NVSS, the spectral index between 325 and 1400MHz, the redshift of the host galaxy, the angular size of the radio source in arcminutes, the resulting projected linear size in Mpc (using H_0=50km/s/Mpc, q_0_=0.5) and the radio luminosity at an emitted frequency of 325MHz.
- ID:
- ivo://CDS.VizieR/J/ApJ/862/2
- Title:
- Post-starburst galaxy ages from SDSS
- Short Name:
- J/ApJ/862/2
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Detailed modeling of the recent star formation histories (SFHs) of post-starburst (or "E+A") galaxies is impeded by the degeneracy between the time elapsed since the starburst ended (post-burst age), the fraction of stellar mass produced in the burst (burst strength), and the burst duration. To resolve this issue, we combine GALEX ultraviolet photometry, SDSS photometry and spectra, and new stellar population synthesis models to fit the SFHs of 532 post-starburst galaxies. In addition to an old stellar population and a recent starburst, 48% of the galaxies are best fit with a second recent burst. Lower stellar mass galaxies (logM*/M_{sun}_<10.5) are more likely to experience two recent bursts, and the fraction of their young stellar mass is more strongly anticorrelated with their total stellar mass. Applying our methodology to other, younger post-starburst samples, we identify likely progenitors to our sample and examine the evolutionary trends of molecular gas and dust content with post-burst age. We discover a significant (4{sigma}) decline, with a 117-230Myr characteristic depletion time, in the molecular gas to stellar mass fraction with the post-burst age. The implied rapid gas depletion rate of 2-150M_{sun}_/yr cannot be due to current star formation, given the upper limits on the current star formation rates in these post- starbursts. Nor are stellar winds or supernova feedback likely to explain this decline. Instead, the decline points to the expulsion or destruction of molecular gas in outflows, a possible smoking gun for active galactic nucleus feedback.
- ID:
- ivo://CDS.VizieR/J/AJ/142/153
- Title:
- Precision spectrophotometry at the level of 0.1%
- Short Name:
- J/AJ/142/153
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Accurate relative spectrophotometry is critical for many science applications. Small wavelength-scale residuals in the flux calibration can significantly impact the measurements of weak emission and absorption features in the spectra. Using Sloan Digital Sky Survey data, we demonstrate that the average spectra of carefully selected red-sequence galaxies can be used as a spectroscopic standard to improve the relative spectrophotometry precision to 0.1% on small wavelength scales (from a few to hundreds of Angstroms). We achieve this precision by comparing stacked spectra across tiny redshift intervals. The redshift intervals must be small enough that any systematic stellar population evolution is minimized and is less than the spectrophotometric uncertainty. This purely empirical technique does not require any theoretical knowledge of true galaxy spectra. It can be applied to all large spectroscopic galaxy redshift surveys that sample a large number of galaxies in a uniform population.
- ID:
- ivo://CDS.VizieR/J/ApJ/765/9
- Title:
- Predicted CO and [CII] fluxes of HUDF galaxies
- Short Name:
- J/ApJ/765/9
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Modern (sub-)millimeter/radio interferometers such as ALMA, JVLA, and the PdBI successor NOEMA will enable us to measure the dust and molecular gas emission from galaxies that have luminosities lower than the Milky Way, out to high redshifts and with unprecedented spatial resolution and sensitivity. This will provide new constraints on the star formation properties and gas reservoir in galaxies throughout cosmic times through dedicated deep field campaigns targeting the CO/[C II] lines and dust continuum emission in the (sub-)millimeter regime. In this paper, we present empirical predictions for such line and continuum deep fields. We base these predictions on the deepest available optical/near-infrared Advanced Camera for Surveys and NICMOS data on the Hubble Ultra Deep Field (over an area of about 12arcmin^2^). Using a physically motivated spectral energy distribution model, we fit the observed optical/near-infrared emission of 13099 galaxies with redshifts up to z=5, and obtain median-likelihood estimates of their stellar mass, star formation rate, dust attenuation, and dust luminosity. We combine the attenuated stellar spectra with a library of infrared emission models spanning a wide range of dust temperatures to derive statistical constraints on the dust emission in the infrared and (sub-)millimeter which are consistent with the observed optical/near-infrared emission in terms of energy balance. This allows us to estimate, for each galaxy, the (sub-)millimeter continuum flux densities in several ALMA, PdBI/NOEMA, and JVLA bands. As a consistency check, we verify that the 850{mu}m number counts and extragalactic background light derived using our predictions are consistent with previous observations. Using empirical relations between the observed CO/[C II] line luminosities and the infrared luminosity of star-forming galaxies, we infer the luminosity of the CO(1-0) and [C II] lines from the estimated infrared luminosity of each galaxy in our sample.
