- ID:
- ivo://CDS.VizieR/J/MNRAS/436/1919
- Title:
- SCUBA observations of COSMOS galaxies
- Short Name:
- J/MNRAS/436/1919
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep 450{mu}m and 850{mu}m observations of a large, uniformly covered 394arcmin^2^ area in the Cosmic Evolution Survey (COSMOS) field obtained with the Scuba-2 instrument on the James Clerk Maxwell Telescope (JCMT). We achieve root-mean-square noise values of {sigma}_450_=4.13mJy and {sigma}_850_=0.80mJy. The differential and cumulative number counts are presented and compared to similar previous works. Individual point sources are identified at >3.6{sigma} significance, a threshold corresponding to a 3-5% sample contamination rate. We identify 78 sources at 450{mu}m and 99 at 850{mu}m, with flux densities S_450_=13-37mJy and S_850_=2-16mJy. Only 62-76% of 450{mu}m sources are 850{mu}m detected and 61-81% of 850{mu}m sources are 450{mu}m detected. The positional uncertainties at 450{mu}m are small (1-2.5 arcsec) and therefore allow a precise identification of multiwavelength counterparts without reliance on detection at 24{mu}m or radio wavelengths; we find that only 44% of 450{mu}m sources and 60% of 850{mu}m sources have 24{mu}m or radio counterparts. 450{mu}m selected galaxies peak at <z>=1.95+/-0.19 and 850{mu}m selected galaxies peak at <z>=2.16+/-0.11. The two samples occupy similar parameter space in redshift and luminosity, while their median SED peak wavelengths differ by ~20-50{mu}m (translating to {Delta}T_dust_=8-12K, where 450{mu}m selected galaxies are warmer). The similarities of the 450{mu}m and 850{mu}m populations, yet lack of direct overlap between them, suggests that submillimetre surveys conducted at any single far-infrared wavelength will be significantly incomplete (>~30%) at censusing infrared-luminous star formation at high z.
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Search Results
- ID:
- ivo://CDS.VizieR/J/MNRAS/477/1099
- Title:
- SCUBA-2 850um obs. of Herschel gal.
- Short Name:
- J/MNRAS/477/1099
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- High-redshift, luminous, dusty star-forming galaxies (DSFGs) constrain the extremity of galaxy formation theories. The most extreme are discovered through follow-up on candidates in large area surveys. Here, we present extensive 850um SCUBA-2 follow-up observations of 188 red DSFG candidates from the Herschel Multitiered Extragalactic Survey (HerMES) Large Mode Survey, covering 274deg^2^. We detected 87% with a signal-to-noise ratio >3 at 850um. We introduce a new method for incorporating the confusion noise in our spectral energy distribution fitting by sampling correlated flux density fluctuations from a confusion limited map. The new 850um data provide a better constraint on the photometric redshifts of the candidates, with photometric redshift errors decreasing from {sigma}_z_/(1+z)~0.21 to 0.15. Comparison spectroscopic redshifts also found little bias (<(z-z_spec_)/(1+z_spec_)>=0.08). The mean photometric redshift is found to be 3.6 with a dispersion of 0.4 and we identify 21 DSFGs with a high probability of lying at z>4. After simulating our selection effects we find number counts are consistent with phenomenological galaxy evolution models. There is a statistically significant excess of WISE-1 and SDSS sources near our red galaxies, giving a strong indication that lensing may explain some of the apparently extreme objects. Nevertheless, our sample includes examples of galaxies with the highest star formation rates in the Universe (>>10^3^M_{sun}_/yr).
- ID:
- ivo://CDS.VizieR/J/A+A/626/A15
- Title:
- Sculptor Red Giant Branch stars abundances
- Short Name:
- J/A+A/626/A15
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present detailed chemical abundances for 99 Red Giant Branch stars in the centre of the Sculptor dwarf spheroidal galaxy, which have been obtained from high-resolution VLT/FLAMES spectroscopy. The abundances of Li, Na, alpha-elements (O, Mg, Si, Ca Ti), iron-peak elements (Sc, Cr, Fe, Co, Ni, Zn), r- and s-process elements (Ba, La, Nd, Eu) were all derived using stellar atmosphere models and semi-automated analysis techniques. The iron abundances, covering the range -2.3<[Fe/H]<-0.9, populate the whole metallicity distribution of the galaxy with the exception of the very low metallicity tail. There is a marked decrease in [{alpha}/Fe] over our sample, from the Galactic halo plateau value at low [Fe/H] and then, after a 'knee', a decrease to sub-solar [alpha/Fe] at high [Fe/H]. This is consistent with products of core-collapse supernovae dominating at early times, followed by the onset of supernovae type Ia as early as ~12Gyr ago. The products from low-mass AGB stars, as traced by the s-process, also participate in the chemical evolution of Sculptor with a timescale comparable to that of supernovae type Ia. However, the r-process is consistent with having no time delay relative to core-collapse supernovae, at least at the later stages of the chemical evolution in Sculptor. Using the simple and well-behaved chemical evolution of Sculptor, we further derive empirical constraints on the relative importance of massive stars and supernovae type Ia to the nucleosynthesis of individual iron-peak and alpha-elements. The most important contribution of supernovae typeIa is to the iron-peak elements: Fe, Cr and Mn; but there is also a modest but non-negligible contribution to both the heavier alpha-elements: S, Ca and Ti, and some of the iron-peak elements: Sc and Co. We see only very small or no contribution to O, Mg, Ni and Zn from supernovae type Ia in Sculptor. The observed chemical abundances in Sculptor show no evidence of a significantly different initial mass function, compared to that of the Milky Way. With the exception of neutron-capture elements at low [Fe/H], the scatter around mean trends in Sculptor for [Fe/H]>-2.3 is extremely low, and compatible with observational errors. Combined with the small scatter in the age-elemental abundances relation, this calls for an efficient mixing of metals in the gas in the centre of Sculptor since ~12Gyr ago.
- ID:
- ivo://CDS.VizieR/J/ApJ/657/738
- Title:
- SDF galaxies multi-photometry
- Short Name:
- J/ApJ/657/738
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- SDF (Subaru Deep Field) line-emitting galaxies in four narrow-band filters at low and intermediate redshifts are presented. Broadband colors, follow-up optical spectroscopy, and multiple NB filters are used to distinguish H{alpha}, [OII], and [OIII] emitters at z=0.07-1.47 to construct their LFs. These LFs are derived down to faint magnitudes, allowing for an accurate determination of the faint-end slope. With a large (N~200) sample for each redshift interval, a Schechter profile is fitted to each LF.
- ID:
- ivo://CDS.VizieR/J/A+A/525/A157
- Title:
- SDSS automated morphology classification
- Short Name:
- J/A+A/525/A157
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an automated morphological classification in 4 types (E, S0, Sab, Scd) of ~700 000 galaxies from the SDSS DR7 spectroscopic sample based on support vector machines. The main new property of the classification is that we associate a probability to each galaxy of being in the four morphological classes instead of assigning a single class. The classification is therefore better adapted to nature where we expect a continuous transition between different morphological types. The algorithm is trained with a visual classification and then compared to several independent visual classifications including the Galaxy Zoo first-release catalog. We find a very good correlation between the automated classification and classical visual ones.
- ID:
- ivo://CDS.VizieR/J/MNRAS/418/244
- Title:
- SDSS-based Polar Ring Catalogue
- Short Name:
- J/MNRAS/418/244
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Galaxies with polar rings (PRGs) are a unique class of extragalactic objects. Using these, we can investigate a wide range of problems, linked to the formation and evolution of galaxies, and we can study the properties of their dark haloes. The progress that has been made in the study of PRGs has been constrained by the small number of known objects of this type. The Polar Ring Catalogue (PRC) by Whitmore et al. (1990AJ....100.1489W) and their photographic atlas of PRGs and related objects includes 157 galaxies. At present, there are only about two dozen kinematically confirmed galaxies in this PRG class, mostly from the PRC. We present a new catalogue of PRGs, supplementing the PRC and significantly increasing the number of known candidate PRGs. The catalogue is based on the results of the original Galaxy Zoo project. Within this project, volunteers performed visual classifications of nearly a million galaxies from the Sloan Digital Sky Survey (SDSS). Based on the preliminary classifications of the Galaxy Zoo, we viewed more than 40000 images of the SDSS and selected 275 galaxies to include in our catalogue.
- ID:
- ivo://CDS.VizieR/J/ApJS/210/3
- Title:
- SDSS bulge, disk and total stellar mass estimates
- Short Name:
- J/ApJS/210/3
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of bulge, disk, and total stellar mass estimates for ~660000 galaxies in the Legacy area of the Sloan Digital Sky Survey Data (SDSS) Release 7. These masses are based on a homogeneous catalog of g- and r-band photometry described by Simard et al. (2011, Cat. J/ApJS/196/11), which we extend here with bulge+disk and Sersic profile photometric decompositions in the SDSS u, i, and z bands. We discuss the methodology used to derive stellar masses from these data via fitting to broadband spectral energy distributions (SEDs), and show that the typical statistical uncertainty on total, bulge, and disk stellar mass is ~0.15 dex. Despite relatively small formal uncertainties, we argue that SED modeling assumptions, including the choice of synthesis model, extinction law, initial mass function, and details of stellar evolution likely contribute an additional 60% systematic uncertainty in any mass estimate based on broadband SED fitting. We discuss several approaches for identifying genuine bulge+disk systems based on both their statistical likelihood and an analysis of their one-dimensional surface-brightness profiles, and include these metrics in the catalogs. Estimates of the total, bulge and disk stellar masses for both normal and dust-free models and their uncertainties are made publicly available here.
- ID:
- ivo://CDS.VizieR/J/AJ/128/1002
- Title:
- SDSS candidate type II quasars. II
- Short Name:
- J/AJ/128/1002
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Type II quasars are luminous active galactic nuclei (AGNs) whose central engines and broad-line regions are obscured by intervening material; such objects only recently have been discovered in appreciable numbers. We study the multiwavelength properties of 291 type II AGN candidates (0.3<z<0.8) selected on the basis of their optical emission-line properties from the spectroscopic database of the Sloan Digital Sky Survey (Cat. <J/AJ/126/2579>). This sample includes about 150 objects luminous enough to be classified as type II quasars. We matched the sample to the FIRST (20cm, Cat.<VIII/71>), IRAS (12-100{mu}m, Cat. <II/125>), 2MASS (JHK_s_, Cat. <II/246>), and RASS (0.1-2.4keV, Cat. <IX/29>) surveys. Roughly 10% of optically selected type II AGN candidates are radio-loud, comparable to the AGN population as a whole. About 40 objects are detected by IRAS at 60 and/or 100{mu}m, and the inferred mid/far-IR luminosities lie in the range L=10^45^-3x10^46^ergs/s. Average IR-to-[OIII]{lambda}5007 ratios of objects in our sample are consistent with those of other AGNs. Objects from our sample are 10 times less likely to have soft X-ray counterparts in RASS than type I AGNs with the same redshifts and [OIII]{lambda}5007 luminosities. The few type II AGN candidates from our sample that are detected by RASS have harder X-ray spectra than those of type I AGNs. The multiwavelength properties of the type II AGN candidates from our sample are consistent with their interpretation as powerful obscured AGNs.
- ID:
- ivo://CDS.VizieR/J/AJ/136/2115
- Title:
- SDSS/CIG galaxies classification
- Short Name:
- J/AJ/136/2115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a re-evaluation of the optical morphology for 549 galaxies from the Catalog of Isolated Galaxies in the Northern Hemisphere (CIG) that are available in the Sloan Digital Sky Survey (SDSS; DR6). Both the high resolution and high dynamic range of the SDSS images and our semiautomatic image processing scheme allow for a major quality and uniform morphological analysis. The processing scheme includes (1) sky-subtracted, cleaned, and logarithmic scaled g-band images, (2) filtered-enhanced versions of the images in (1), and (3) the corresponding red-green-blue (RGB) composed images available in the SDSS database. We propose an empirical method to distinguishing between E, S0, and Sa candidates through an additional analysis of (4) the surface brightness, position angle, ellipticity and A_4_B_4_ coefficients of the Fourier series expansion profiles. An atlas of mosaics containing (1), (2), and (3) images for Sab-Sm/Irr types and (1), (2), (3), (4) images for E/S0/Sa types was produced and is available on the Web site, http://132.248.1.210.
- ID:
- ivo://CDS.VizieR/J/ApJS/223/20
- Title:
- SDSS-DR8 galaxies classified by WND-CHARM
- Short Name:
- J/ApJS/223/20
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have applied computer analysis to classify the broad morphological types of ~3x10^6^ Sloan Digital Sky Survey (SDSS) galaxies. For each galaxy, the catalog provides the DR8 object ID, the R.A., the decl., and the certainty for the automatic classification as either spiral or elliptical. The certainty of the classification allows us to control the accuracy of a subset of galaxies by sacrificing some of the least certain classifications. The accuracy of the catalog was tested using galaxies that were classified by the manually annotated Galaxy Zoo catalog. The results show that the catalog contains ~900000 spiral galaxies and ~600000 elliptical galaxies with classification certainty that has a statistical agreement rate of ~98% with the Galaxy Zoo debiased "superclean" data set. The catalog also shows that objects assigned by the SDSS pipeline with a relatively high redshift (z>0.4) can have clear visual spiral morphology.
