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1051. Faraday rotation from magnesium II absorbers
ID:
ivo://CDS.VizieR/J/ApJ/795/63
Title:
Faraday rotation from magnesium II absorbers
Short Name:
J/ApJ/795/63
Date:
21 Oct 2021
Publisher:
CDS
Description:
Strong singly ionized magnesium (Mg II) absorption lines in quasar spectra typically serve as a proxy for intervening galaxies along the line of sight. Previous studies have found a correlation between the number of these Mg II absorbers and the Faraday rotation measure (RM) at ~5 GHz. We cross-match a sample of 35752 optically identified non-intrinsic Mg II absorption systems with 25649 polarized background radio sources for which we have measurements of both the spectral index and RM at 1.4 GHz. We use the spectral index to split the resulting sample of 599 sources into flat-spectrum and steep-spectrum subsamples. We find that our flat-spectrum sample shows significant (~3.5{sigma}) evidence for a correlation between Mg II absorption and RM at 1.4 GHz, while our steep-spectrum sample shows no such correlation. We argue that such an effect cannot be explained by either luminosity or other observational effects, by evolution in another confounding variable, by wavelength-dependent polarization structure in an active galactic nucleus, by the Galactic foreground, by cosmological expansion, or by partial coverage models. We conclude that our data are most consistent with intervenors directly contributing to the Faraday rotation along the line of sight, and that the intervening systems must therefore have coherent magnetic fields of substantial strength (B{bar}=1.8+/-0.4{mu}G). Nevertheless, the weak nature of the correlation will require future high-resolution and broadband radio observations in order to place it on a much firmer statistical footing.
1052. Faraday rotation in Cen A
ID:
ivo://CDS.VizieR/J/ApJ/707/114
Title:
Faraday rotation in Cen A
Short Name:
J/ApJ/707/114
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the results of an Australia Telescope Compact Array 1.4GHz spectropolarimetric aperture synthesis survey of 34deg^2^ centered on Centaurus A-NGC 5128. A catalog of 1005 extragalactic compact radio sources in the field to a continuum flux density of 3mJy/beam is provided along with a table of Faraday rotation measures (RMs) and linear polarized intensities for the 28% of sources with high signal to noise in linear polarization. We use the ensemble of 281 background polarized sources as line-of-sight probes of the structure of the giant radio lobes of Centaurus A. This is the first time such a method has been applied to radio galaxy lobes and we explain how it differs from the conventional methods that are often complicated by depth and beam depolarization effects. Assuming a magnetic field strength in the lobes of 1.3B1uG, where B1=1 is implied by equipartition between magnetic fields and relativistic particles, the upper limit we derive on the maximum possible difference between the average RM of 121 sources behind Centaurus A and the average RM of the 160 sources along sightlines outside Centaurus A implies an upper limit on the volume-averaged thermal plasma density in the giant radio lobes of <ne><5x10^-5^B1^-1^cm^-3^. We use an RM structure function analysis and report the detection of a turbulent RM signal, with rms=17rad/m^2^ and scale size 0.3deg, associated with the southern giant lobe. We cannot verify whether this signal arises from turbulent structure throughout the lobe or only in a thin skin (or sheath) around the edge, although we favor the latter. The RM signal is modeled as possibly arising from a thin skin with a thermal plasma density equivalent to the Centaurus intragroup medium density and a coherent magnetic field that reverses its sign on a spatial scale of 20kpc. For a thermal density of n1 10^-3^cm^-3^, the skin magnetic field strength is 0.8n1^-1^uG.
1053. Far-infrared SED measurements of massive galaxies
ID:
ivo://CDS.VizieR/J/ApJ/869/4
Title:
Far-infrared SED measurements of massive galaxies
Short Name:
J/ApJ/869/4
Date:
21 Oct 2021
Publisher:
CDS
Description:
Massive Population II galaxies undergoing the first phase of vigorous star formation after the initial Population III stage should have high energy densities and silicate-rich interstellar dust. We have modeled the resulting far-infrared spectral energy distributions (SEDs), demonstrating that they are shifted substantially to bluer ("warmer") wavelengths relative to the best fitting ones at z~3, and with strong outputs in the 10-40{mu}m range. When combined with a low level of emission by carbon dust, their SEDs match that of Haro 11, a local moderately low-metallicity galaxy undergoing a very young and vigorous starburst that is likely to approximate the relevant conditions in young Population II galaxies. We expect to see similar SEDs at high redshifts (z>~5) given the youth of galaxies at this epoch. In fact, we find a progression with redshift in observed galaxy SEDs, from those resembling local ones at 2<~z<4 to a closer resemblance with Haro 11 at 5<~z<7. In addition to the insight on conditions in high-redshift galaxies, this result implies that estimates of the total infrared luminosities at z~6 based on measurements near {lambda}~1mm can vary by factors of 2-4, depending on the SED template used. Currently popular modified blackbodies or local templates can result in significant underestimates compared with the preferred template based on the SED of Haro 11.
1054. Far infrared Seyfert galaxies
ID:
ivo://CDS.VizieR/J/other/PBeiO/18.7
Title:
Far infrared Seyfert galaxies
Short Name:
J/other/PBeiO/18
Date:
21 Oct 2021
Publisher:
CDS
Description:
Confusing sources of Seyfert and HII galaxies in IRAS point source catalogue may be caused by companion objects of those galaxies. Comparison between confused galaxies and non-confused galaxies have been made. The preliminary comparison shows that confused galaxies are fainter than nonconfused galaxies generally, and colour diagrams illustrate that confused Seyferts are separated from nonconfused Seyferts obviously.
1055. Far-IR and H{alpha} fluxes in galaxies
ID:
ivo://CDS.VizieR/J/ApJ/703/1672
Title:
Far-IR and H{alpha} fluxes in galaxies
Short Name:
J/ApJ/703/1672
Date:
21 Oct 2021
Publisher:
CDS
Description:
We combine H{alpha} emission-line and infrared (IR) continuum measurements of two samples of nearby galaxies to derive dust attenuation-corrected star formation rates (SFRs). We use a simple energy balance based method that has been applied previously to HII regions in the Spitzer Infrared Nearby Galaxies Survey, and extend the methodology to integrated measurements of galaxies. We find that our composite H{alpha}+IR based SFRs are in excellent agreement with attenuation-corrected SFRs derived from integrated spectrophotometry, over the full range of SFRs (0.01-80M_{sun}_/yr) and attenuations (0-2.5mag) studied. The calibrations differ significantly from those obtained for HII regions, with the difference attributable to a more evolved population of stars heating the dust. Our results are consistent with a significant component of diffuse dust (the "IR cirrus" component) that is heated by a non-star-forming population.
1056. Far-IR properties of VCC galaxies
ID:
ivo://CDS.VizieR/J/MNRAS/428/1880
Title:
Far-IR properties of VCC galaxies
Short Name:
J/MNRAS/428/1880
Date:
21 Oct 2021
Publisher:
CDS
Description:
The Herschel Virgo Cluster Survey (HeViCS) is the deepest, confusion-limited survey of the Virgo Cluster at far-infrared (FIR) wavelengths. The entire survey at full depth covers ~55deg^2^ in five bands (100-500um), encompassing the areas around the central dominant elliptical galaxies (M87, M86 and M49) and extends as far as the NW cloud, the W cloud and the Southern extension. The survey extends beyond this region with lower sensitivity so that the total area covered is 84 deg2. In this paper we describe the data, the data acquisition techniques and present the detection rates of the optically selected Virgo Cluster Catalogue (VCC). We detect 254 (34%) of 750 VCC galaxies found within the survey boundary in at least one band and 171 galaxies are detected in all five bands. For the remainder of the galaxies we have measured strict upper limits for their FIR emission.
1057. Far-IR star formation rate indicators
ID:
ivo://CDS.VizieR/J/ApJ/714/1256
Title:
Far-IR star formation rate indicators
Short Name:
J/ApJ/714/1256
Date:
21 Oct 2021
Publisher:
CDS
Description:
Spitzer data at 24, 70, and 160um and ground-based H{alpha} images are analyzed for a sample of 189 nearby star-forming and starburst galaxies to investigate whether reliable star formation rate (SFR) indicators can be defined using the monochromatic infrared dust emission centered at 70 and 160um. We compare recently published recipes for SFR measures using combinations of the 24um and observed H{alpha} luminosities with those using 24um luminosity alone. From these comparisons, we derive a reference SFR indicator for use in our analysis. Linear correlations between SFR and the 70um and 160um luminosity are found for L(70)>~1.4x10^42^erg/s and L(160)>~2x10^42^erg/s, corresponding to SFR>~0.1-0.3M_{sun}_/yr, and calibrations of SFRs based on L(70) and L(160) are proposed. Below those two luminosity limits, the relation between SFR and 70um (160um) luminosity is nonlinear and SFR calibrations become problematic. A more important limitation is the dispersion of the data around the mean trend, which increases for increasing wavelength.
1058. Far IR survey in the Lockman Hole
ID:
ivo://CDS.VizieR/J/A+A/413/843
Title:
Far IR survey in the Lockman Hole
Short Name:
J/A+A/413/843
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present the catalogs and source counts for the C_90_ (reference wavelength of 90um) and C_160_ (170um) bands, which were extracted from our analysis of an ISO deep far-infrared survey conducted as part of the Japan/UH ISO cosmology project. The total survey area is ~0.9deg^2^ in two fields within the Lockman Hole. The analysis consists of source extraction using the IRAF DAOPHOT package and simulations carried out by adding artificial sources to the maps to estimate the detection rate, the flux bias, the positional accuracy, and the noise.
1059. Far Ultraviolet Spectroscopic Explorer
ID:
ivo://archive.stsci.edu/fuse
Title:
Far Ultraviolet Spectroscopic Explorer
Short Name:
FUSE
Date:
22 Jul 2020 21:29:31
Publisher:
Space Telescope Science Institute Archive
Description:
The Far Ultraviolet Spectroscopic Explorer (FUSE), launched on June 24, 1999, covers the 905-1187 Å spectral region and will obtain high resolution spectra of hot and cool stars, AGNs, supernova remnants, planetary nebulae, solar system objects as well as perform detailed studies of the interstellar medium. FUSE will be able to observe sources 10 000 times fainter than Copernicus, an early FUV mission, and has superior resolving power than the Hopkins Ultraviolet Telescope (HUT) and the Berkeley Spectrograph (BEFS) and the Tübingen Echelle Spectrograph (TUES) of the Orbiting Retrievable Far and Extreme Ultraviolet Spectrometers (ORFEUS). FUSE was planned for a 3 year lifetime with funding for an additional 2 years expected.
1060. Far-ultraviolet variable sources in M31
ID:
ivo://CDS.VizieR/J/AJ/161/215
Title:
Far-ultraviolet variable sources in M31
Short Name:
J/AJ/161/215
Date:
16 Mar 2022 11:52:04
Publisher:
CDS
Description:
The Ultraviolet Imaging Telescope (UVIT) on board the AstroSat observatory has imaged the Andromeda galaxy (M31) from 2017 to 2019 in the far- and near-UV (FUV and NUV) with the high spatial resolution of ~1". The survey covered the large sky area of M31 with a set of observations (Fields), each 28' in diameter. Field 1 was observed in two epochs with the F148W filter, separated by ~1133days (~3.10yr). The 6.4kpc diameter Field 1 (at the distance of M31) includes a substantial part of the inner spiral arms of the galaxy. We identify UVIT sources in both epochs of Field 1 and obtain catalogs of sources that are variable in FUV at >3{sigma} and >5{sigma} confidence level. The fraction of FUV-variable sources is higher for brighter sources, and the fraction is higher in the two main spiral arms compared to other areas. This is evidence that a significant fraction of the FUV variables are associated with hot young stars. Source counterparts are found for 42 of the 86 >5{sigma} FUV variables using existing catalogs. The counterparts include 10 star clusters, 6 HII regions, 5 regular or semiregular variables, 6 other variables, and 6 nova or nova candidates. The UVIT FUV-NUV and FUV-FUV color-magnitude diagrams confirm the association of most of the FUV variables with hot young stars. A catalog of UVIT photometry for the variable sources is presented.

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