- ID:
- ivo://CDS.VizieR/J/MNRAS/455/370
- Title:
- Predicted LIR for SDSS galaxies
- Short Name:
- J/MNRAS/455/370
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The total infrared (IR) luminosity (L_IR_) can be used as a robust measure of a galaxy's star formation rate (SFR), even in the presence of an active galactic nucleus (AGN), or when optical emission lines are weak. Unfortunately, existing all sky far-IR surveys, such as the Infrared Astronomical Satellite (IRAS) and AKARI, are relatively shallow and are biased towards the highest SFR galaxies and lowest redshifts. More sensitive surveys with the Herschel Space Observatory are limited to much smaller areas. In order to construct a large sample of L_IR_ measurements for galaxies in the nearby Universe, we employ artificial neural networks (ANNs), using 1136 galaxies in the Herschel Stripe 82 sample as the training set. The networks are validated using two independent data sets (IRAS and AKARI) and demonstrated to predict the L_IR_ with a scatter {sigma}~0.23dex, and with no systematic offset. Importantly, the ANN performs well for both star-forming galaxies and those with an AGN. A public catalogue is presented with our L_IR_ predictions which can be used to determine SFRs for 331926 galaxies in the Sloan Digital Sky Survey (SDSS), including ~129000 SFRs for AGN-dominated galaxies for which SDSS SFRs have large uncertainties.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/421/1569
- Title:
- Properties of 18286 SDSS radio galaxies
- Short Name:
- J/MNRAS/421/1569
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A sample of 18286 radio-loud active galactic nuclei (AGN) is presented, constructed by combining the seventh data release of the Sloan Digital Sky Survey with the NRAO (National Radio Astronomy Observatory) VLA (Very Large Array) Sky Survey (NVSS) and the Faint Images of the Radio Sky at Twenty centimetres (FIRST) survey. Using this sample, the differences between radio galaxies of "high-excitation" ("quasar-mode"; hereafter HERG) and "low-excitation" ("radio-mode"; LERG) are investigated.
- ID:
- ivo://CDS.VizieR/J/MNRAS/468/4006
- Title:
- Proto-cluster candidate fields
- Short Name:
- J/MNRAS/468/4006
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present SCUBA-2 follow-up of 61 candidate high-redshift Planck sources. Of these, 10 are confirmed strong gravitational lenses and comprise some of the brightest such submm sources on the observed sky, while 51 are candidate proto-cluster fields undergoing massive starburst events. With the accompanying Herschel-Spectral and Photometric Imaging Receiver observations and assuming an empirical dust temperature prior of 34^+13^_-9_K, we provide photometric redshift and far-IR luminosity estimates for 172 SCUBA-2-selected sources within these Planck overdensity fields. The redshift distribution of the sources peak between a redshift of 2 and 4, with one-third of the sources having S_500_/S_350_>1. For the majority of the sources, we find far-IR luminosities of approximately 10^13^L_{sun}_, corresponding to star formation rates of around 1000M_{sun}_/yr. For S_850_>8mJy sources, we show that there is up to an order of magnitude increase in star formation rate density and an increase in uncorrected number counts of 6 for S_850_>8mJy when compared to typical cosmological survey fields. The sources detected with SCUBA-2 account for only approximately 5 per cent of the Planck flux at 353 GHz, and thus many more fainter sources are expected in these fields.
264. PSCz catalog
- ID:
- ivo://CDS.VizieR/VII/221
- Title:
- PSCz catalog
- Short Name:
- VII/221
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The PSCz survey consists of redshifts, infra-red and optical photometry, and assorted other information for 18351 IRAS sources, mostly selected from the Point Source Catalog. The survey was designed to select almost all galaxies with flux brighter than 0.595Jy at 60 microns, over the 84% of the sky with extinction small enough that reliable and complete optical identification and spectroscopy was possible. Some of the sources are not galaxies and some are multiple entries for the same galaxy as described below. There are in total 15411 galaxies or possible galaxies, for which redshifts are available for 14677. The galaxies without redshift are mostly distant or at low latitude, as described below. Many of these galaxies have now been observed as part of the BTP project (Saunders et al 1999, astro-ph/9909174 "The Behind the Plane Survey"), and their redshifts will be included in future revisions of the catalogue. The main catalogue is "pscz.dat". There is also a short version of the catalogue, "psczvs.dat", containing sufficient information for most studies. They correspond to the version 2.2.
- ID:
- ivo://CDS.VizieR/J/MNRAS/432/62
- Title:
- PS1 MDS X-ray selected galaxy clusters
- Short Name:
- J/MNRAS/432/62
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a pilot study for the extended Massive Cluster Survey (eMACS), a comprehensive search for distant, X-ray luminous galaxy clusters at z>0.5. Our pilot study applies the eMACS concept to the 71deg^2^ area extended by the 10 fields of the Pan-STARRS1 (PS1) Medium Deep Survey (MDS). Candidate clusters are identified by visual inspection of PS1 images in the g, r, i and z bands in a 5x5arcmin^2^ region around X-ray sources detected in the ROSATAll-Sky Survey (RASS).
- ID:
- ivo://CDS.VizieR/J/MNRAS/308/897
- Title:
- QDOT all-sky IRAS redshift survey
- Short Name:
- J/MNRAS/308/897
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The catalogue from the QDOT survey consists of infrared properties and redshifts of an all-sky sample of 2387 IRAS galaxies brighter than the IRAS PSC 60{mu}m completeness limit (S_60_>0.6Jy), sparsely sampled at a rate of one-in-six. At |b|>10{deg}, after removing a small number of Galactic sources, the redshift completeness is better than 98% (2086/2127). New redshifts for 1401 IRAS sources were obtained in 1985-88 at several telescopes (see "Note (8)" below) to complete the catalogue; the measurement and reduction of these are described, and the new redshifts tabulated here. We also tabulate all sources at |b|>10{deg} with no redshift so far, and sources with conflicting alternative redshifts either from our own work, or from published velocities. A list of 95 ultraluminous galaxies (i.e. with L(60{mu}m)>10^12^L_{sun}_) is also provided.
- ID:
- ivo://CDS.VizieR/J/MNRAS/447/3856
- Title:
- QSO-galaxy pairs from SDSS
- Short Name:
- J/MNRAS/447/3856
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometric and spectroscopic measurements of 53 QSO-galaxy pairs from the Sloan Digital Sky Survey (SDSS), where nebular emission lines from a 0<z<0.84 foreground galaxy are detected in the fibre spectra of a background QSO, bringing the overall sample to 103 QSO-galaxy pairs detected in the SDSS. We here study the nature of these systems. Detected foreground galaxies appear at impact parameters between 0.37 and 12.68 kpc. The presence of oxygen and Balmer emission lines allows us to determine the emission line metallicities for our sample, which are on average supersolar in value. Star formation rates for our sample are in the range 0.01-12M_{sun}_/yr. We utilize photometric redshift fitting techniques to estimate the M* values of our galaxies (logM*=7.34-11.54), and extrapolate this relationship to those galaxies with no imaging detections. Where available, we measure the absorption features present in the QSO spectrum due to the foreground galaxy and the relationships between their rest equivalent widths. We report an anticorrelation between impact parameter and E(B-V)(g-i), as well as a correlation between galaxy colour (u- r) and E(B-V)(g-i). We find that our sample is one of late-type, star-forming galaxies comparable to field galaxies in a similar redshift range, providing important clues to better understand absorption systems. These galaxies represent a sample of typical galaxies in the local Universe for which abundances, extinction, morphology, and absorption properties may be measured using background QSOs with great potential for follow-up observations.
- ID:
- ivo://CDS.VizieR/J/MNRAS/434/163
- Title:
- QSOs narrow absorption line variability
- Short Name:
- J/MNRAS/434/163
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results from a time domain study of absorption lines detected in quasar spectra with repeat observations from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7). Beginning with over 4,500 unique time separation baselines of various absorption line species identified in the SDSS DR7 quasar spectra, we create a catalogue of 2,522 quasar absorption line (QAL) systems with two to eight repeat observations, representing the largest, unbiased, and homogeneous collection of multi-epoch absorption systems ever published. To investigate these systems for time-variability of narrow absorption lines, we refine this sample based on the reliability of the system detection, the proximity of pixels with bright sky contamination to individual absorption lines, and the quality of the continuum fit. Variability measurements of this sub-sample based on the absorption line equivalent widths yield a total of 33 systems with indications of significantly variable absorption strengths on time-scales ranging from one day to several years in the rest frame of the absorption system. Of these, at least 10 are from a class known as intervening absorption systems caused by foreground galaxies along the line of sight to the background quasar. This is the first evidence of possible absorption line variability detected in intervening systems, and their short time-scale variations suggest that small-scale structures (~10-100AU) are likely to exist in their host foreground galaxies.
- ID:
- ivo://CDS.VizieR/J/MNRAS/309/48
- Title:
- QSOs redshifts and spectra in ESO/SERC field 927
- Short Name:
- J/MNRAS/309/48
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the spectra and redshifts of 62 quasars, from observations made with the Cerro Tololo Inter-American Observatory (CTIO) 4-m Blanco Telescope. These quasars form part of a total sample of 118 (with 56 having been published previously), which is being used for analysis of structure in the early universe. Quasars of particular interest are noted, including eight broad absorption line (BAL) quasars and two quasars with unusual emission spectra. Finally, we include a short summary of the present status of the large quasar group (LQG) that was discovered by Clowes & Campusano (1991, Cat. J/MNRAS/249/218 and 1994, Cat. J/MNRAS/266/317) from the earlier observations. The quasars are from an area ~25.3deg^2^ of ESO/SERC field 927, which is centred at (B1950) 10h 40m 00s, 05{deg} 00'00".
270. Quasar Candidates
- ID:
- ivo://CDS.VizieR/VII/143
- Title:
- Quasar Candidates
- Short Name:
- VII/143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This data set is based on data in three publications. The positions and magnitudes of quasar candidates discovered on Canada-France Hawaii-Telescope (CFHT) blue green plates are given. Spectroscopy with the Multiple Mirror Telescope (MMT) indicates that 70 percent of the candidates are quasars, and most of the others are white dwarfs or hot subluminous stars. Most of the redshifts are less than z=1.7. Additional spectroscopic observations at Steward Observatory were used. The catalog lists a name based on position, B1950 position, B magnitude, or visual magnitude, redshift, and remarks.
