- ID:
- ivo://CDS.VizieR/J/ApJ/702/1567
- Title:
- Structure of 2MASS edge-on galaxies
- Short Name:
- J/ApJ/702/1567
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of an analysis of the J, H, and Ks Two Micron All Sky Survey (2MASS) images of 139 spiral edge-on galaxies selected from the Revised Flat Galaxies Catalog. The basic structural parameters scale length (h), scale height (z_0_), and central surface brightness of the stellar disks ({mu}_0_) are determined for all selected galaxies in the near-infrared (NIR) bands. The mean relative ratios of the scale heights of the thin stellar disks in the J:H:Ks bands are 1.16:1.08:1.00, respectively. Comparing the scale heights obtained from the NIR bands for the same objects, we estimate the scale heights of the thin stellar disks corrected for the internal extinction. We find that the extinction-corrected scale height is, on average, 11% smaller than that in the K band. Using the extinction-corrected structural parameters, we find that the dark-to-luminous mass ratio is, on average, 1.3 for the galaxies in our sample within the framework of a simplified galactic model. The relative thicknesses of the stellar disks z_0_/h correlates with their face-on central surface brightnesses obtained from the 2MASS images. We also find that the scale height of the stellar disks shows no systematic growth with radius in most of our galaxies.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/659/1176
- Title:
- Study of bars in 180 spiral galaxies
- Short Name:
- J/ApJ/659/1176
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Critical insights on galaxy evolution stem from the study of bars. With the advent of HST surveys that trace bars in the rest-frame optical out to z~1, it is critical to provide a reference baseline for bars at z~0 in the optical band. We present results on bars at z~0 in the optical and NIR based on 180 spirals from OSUBSGS (Eskridge et al., 2002, Cat. J/ApJS/143/73).
- ID:
- ivo://CDS.VizieR/J/other/Ap/54.147
- Title:
- Study of 230 IRAS-FSC galaxies
- Short Name:
- J/other/Ap/54.14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From the cross-correlation of the IRAS FSC catalog with the radio FIRST catalog, 230 infrared galaxies were selected having optical classifications and redshifts from SDSS and NED. To understand the nature of these objects we have compared them with a sample of bright ULIRGs with fluxes f>1Jy at 60-micron and with 14 optically faint IRAS FSC galaxies, showing that IRAS galaxies are not always strong infrared sources. We also have calibrated Star Formation Rates based on luminosities of the PAH feature at 7.7-micron and 1.4GHz radio flux densities, which confirmed the consistency between these two SFRs. We have estimated the extinction for our 230 objects using SFRs calibrated from the PAH feature compared to ultraviolet flux, which shows that only 1% of the ultraviolet continuum typically escapes extinction by dust within a starburst. As our 230 galaxies have no spectra available from Spitzer Space Telescope (SST) archive, to estimate the infrared flux at 7.7 (for SB galaxies) or 8.0 (for AGN and composite) micron, we have used the median ratios of the IRAS fluxes at 25-micron to fluxes at 7.7 or 8.0-micron estimated for each 41.0<logL(IR)<41.9, 42.0<logL(IR)<42.9, 43.0<logL(IR)<43.9, 44.0<logL(IR)<44.9, and 45.0<logL(IR)<45.9 luminosity bins, using objects having spectra from SST archive.
- ID:
- ivo://CDS.VizieR/J/MNRAS/439/1648
- Title:
- Subarcsecond mid-infrared atlas of local AGN
- Short Name:
- J/MNRAS/439/1648
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the first subarcsecond-resolution mid-infrared (MIR) atlas of local active galactic nuclei (AGN). Our atlas contains 253 AGN with a median redshift of z=0.016, and includes all publicly available MIR imaging performed to date with ground-based 8-m class telescopes, a total of 895 independent measurements. Of these, more than 60% are published here for the first time. We detect extended nuclear emission in at least 21% of the objects, while another 19% appear clearly point-like, and the remaining objects cannot be constrained. Where present, elongated nuclear emission aligns with the ionization cones in Seyferts. Subarcsecond resolution allows us to isolate the AGN emission on scales of a few tens of parsecs and to obtain nuclear photometry in multiple filters for the objects. Median spectral energy distributions (SEDs) for the different optical AGN types are constructed and individual MIR 12 and 18um continuum luminosities are computed. These range over more than six orders of magnitude. In comparison to the arcsecond-scale MIR emission as probed by Spitzer, the continuum emission is much lower on subarcsecond scales in many cases. The silicate feature strength is similar on both scales and generally appears in emission (absorption) in type I (II) AGN. However, the polycyclic aromatic hydrocarbon emission appears weaker or absent on subarcsecond scales. The differences of the MIR SEDs on both scales are particularly large for AGN/starburst composites and close-by (and weak) AGN. The nucleus dominates over the total emission of the galaxy only at luminosities >~10^44^erg/s. The AGN MIR atlas is well suited not only for detailed investigation of individual sources but also for statistical studies of AGN unification.
- ID:
- ivo://CDS.VizieR/J/MNRAS/453/1079
- Title:
- Sub-mJy radio sources SF properties
- Short Name:
- J/MNRAS/453/1079
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We investigate the star formation properties of ~800 sources detected in one of the deepest radio surveys at 1.4GHz. Our sample spans a wide redshift range (~0.1-4) and about four orders of magnitude in star formation rate (SFR). It includes both star-forming galaxies (SFGs) and active galactic nuclei (AGNs), further divided into radio-quiet (RQ) and radio-loud objects. We compare the SFR derived from the far-infrared luminosity, as traced by Herschel, with the SFR computed from their radio emission. We find that the radio power is a good SFR tracer not only for pure SFGs but also in the host galaxies of RQ AGNs, with no significant deviation with redshift or specific SFR. Moreover, we quantify the contribution of the starburst activity in the SFG population and the occurrence of AGNs in sources with different level of star formation. Finally, we discuss the possibility of using deep radio survey as a tool to study the cosmic star formation history.
- ID:
- ivo://CDS.VizieR/J/ApJ/639/259
- Title:
- Sub-mm clumps in Orion B South molecular cloud
- Short Name:
- J/ApJ/639/259
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a survey of a 1300arcmin^2^ region of the Orion B South molecular cloud, including NGC 2024, NGC 2023, and the Horsehead Nebula (B33), obtained using the Submillimetre Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope (JCMT). Submillimeter continuum observations at 450 and 850{mu}m are discussed. Using an automated algorithm, 57 discrete emission features ("clumps") are identified in the 850{mu}m map.
- ID:
- ivo://CDS.VizieR/J/A+A/466/1065
- Title:
- submm images of IRAS 05358+3543
- Short Name:
- J/A+A/466/1065
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the small-scale structure of massive star-forming regions through interferometric observations in several (sub)mm wavelength bands. These observations resolve multiple sources, yield mass and column density estimates, and give information about the density profiles as well as the dust and temperature properties.
- ID:
- ivo://CDS.VizieR/J/ApJ/559/307
- Title:
- Sub-mm mapping in Orion B molecular cloud
- Short Name:
- J/ApJ/559/307
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a survey of a 900 arcmin^2^ region of the Orion B molecular cloud, including NGC 2068, NGC 2071, and HH 24/25/26, at 850{mu}m using the Submillimeter Common-User Bolometer Array (SCUBA) on the James Clerk Maxwell Telescope. Following the techniques developed by Johnstone et al. (2000ApJ...545..327J), we identify 75 independent objects and compute size, flux, and degree of central concentration. Comparison with isothermal, pressure-confined, self-gravitating Bonnor-Ebert spheres implies that the clumps have internal temperatures of 20-40K and surface pressures 5.5<log(P/k)[CGS]<6.5. The clump masses span 0.2-12.3M_{sun}_ assuming typical dust temperatures and a dust emissivity {kappa}_850_=0.01cm^2^/g.
- ID:
- ivo://CDS.VizieR/J/A+A/559/A82
- Title:
- Sub-mm observations of IRS43 and IRS63
- Short Name:
- J/A+A/559/A82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A fundamental part of the study of star formation is to place young stellar objects in an evolutionary sequence. Establishing a robust evolutionary classification scheme allows us not only to understand how the Sun was born but also to predict what kind of main sequence star a given protostar will become. Traditionally, low-mass young stellar objects are classified according to the shape of their spectral energy distributions. Such methods are, however, prone to misclassification due to degeneracy and do not constrain the temporal evolution. More recently, young stellar objects have been classified based on envelope, disk, and stellar masses determined from resolved images of their continuum and line emission at submillimeter wavelengths. Through detailed modeling of two Class I sources, we aim at determining accurate velocity profiles and explore the role of freeze-out chemistry in such objects. We present new Submillimeter Array observations of the continuum and HCO^+^ line emission at 1.1mm toward two protostars, IRS 63 and IRS 43 in the Ophiuchus star forming region. The sources were modeled in detail using dust radiation transfer to fit the SED and continuum images and line radiation transfer to produce synthetic position-velocity diagrams. We used a chi^2^ search algorithm to find the best model fit to the data and to estimate the errors in the model variables. Our best fit models present disk, envelope, and stellar masses, as well as the HCO^+^ abundance and inclination of both sources. We also identify a ring structure with a radius of about 200AU in IRS 63. Conclusions. We find that freeze-out chemistry is important in IRS 63 but not for IRS 43. We show that the velocity field in IRS 43 is consistent with Keplerian rotation. Owing molecular depletion, it is not possible to draw a similar conclusion for IRS 63. We identify a ring-shaped structure in IRS 63 on the same spatial scale as the disk outer radius. No such structure is seen in IRS 43. We find that freeze-out chemistry is important in IRS 63 but not for IRS 43. We show that the velocity field in IRS 43 is consistent with Keplerian rotation. Owing molecular depletion, it is not possible to draw a similar conclusion for IRS 63. We identify a ring-shaped structure in IRS 63 on the same spatial scale as the disk outer radius. No such structure is seen in IRS 43.
- ID:
- ivo://CDS.VizieR/J/A+A/579/A115
- Title:
- SUDARE-VOICE variability-selection of AGN
- Short Name:
- J/A+A/579/A115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- One of the most peculiar characteristics of active galactic nuclei (AGNs) is their variability over all wavelengths. This property has been used in the past to select AGN samples and is foreseen to be one of the detection techniques applied in future multi-epoch surveys, complementing photometric and spectroscopic methods. In this paper, we aim to construct and characterise an AGN sample using a multi-epoch dataset in the r band from the SUDARE-VOICE survey. Our work makes use of the VST monitoring programme of an area surrounding the Chandra Deep Field South to select variable sources. We use data spanning a six-month period over an area of 2 square degrees, to identify AGN based on their photometric variability. The selected sample includes 175 AGN candidates with magnitude r<23mag. We distinguish different classes of variable sources through their lightcurves, as well as X-ray, spectroscopic, SED, optical, and IR information overlapping with our survey. We find that 12% of the sample (21/175) is represented by supernovae (SN). Of the remaining sources, 4% (6/154) are stars, while 66% (102/154) are likely AGNs based on the available diagnostics. We estimate an upper limit to the contamination of the variability selected AGN sample =~34%, but we point out that restricting the analysis to the sources with available multi-wavelength ancillary information, the purity of our sample is close to 80% (102 AGN out of 128 non-SN sources with multi-wavelength diagnostics). Our work thus confirms the efficiency of the variability selection method, in agreement with our previous work on the COSMOS field. In addition we show that the variability approach is roughly consistent with the infrared selection.