- ID:
- ivo://CDS.VizieR/J/ApJ/870/104
- Title:
- 1-500um obs. of nearby luminous IR galaxies
- Short Name:
- J/ApJ/870/104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The interstellar medium is a key ingredient that governs star formation in galaxies. We present a detailed study of the infrared (~1-500{mu}m) spectral energy distributions of a large sample of 193 nearby (z~<0.088) luminous infrared galaxies (LIRGs) covering a wide range of evolutionary stages along the merger sequence. The entire sample has been observed uniformly by 2MASS, WISE, Spitzer, and Herschel. We perform a multicomponent decomposition of the spectra to derive physical parameters of the interstellar medium, including the intensity of the interstellar radiation field and the mass and luminosity of the dust. We also constrain the presence and strength of nuclear dust heated by active galactic nuclei. The radiation field of LIRGs tends to have much higher intensity than that of quiescent galaxies, and it increases toward advanced merger stages as a result of the central concentration of the interstellar medium and star formation. The total gas mass is derived from the dust mass and the galaxy stellar mass. We find that the gas fraction of LIRGs is on average ~0.3 dex higher than that of main-sequence star-forming galaxies, rising moderately toward advanced merger stages. All LIRGs have star formation rates that place them above the galaxy star formation main sequence. Consistent with recent observations and numerical simulations, the global star formation efficiency of the sample spans a wide range, filling the gap between normal star-forming galaxies and extreme starburst systems.
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- ID:
- ivo://CDS.VizieR/J/ApJS/249/1
- Title:
- 500um risers with HerMES & SPIRE drop-outs with S2CLS
- Short Name:
- J/ApJS/249/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of our systematic search for the reddest far-infrared (FIR) and submillimeter (sub-mm) galaxies using the data from the Herschel Multi-tiered Extragalactic Survey (HerMES) and the SCUBA2 Cosmological Legacy Survey (S2CLS). The red FIR galaxies are "500{mu}m risers," whose spectral energy distributions increase with wavelength across the three FIR passbands of the Spectral and Photometric Imaging REceiver (SPIRE) of Herschel. Within 106.5deg^2^ of the HerMES fields, we have selected 629 500{mu}m risers. The red sub-mm galaxies are "SPIRE drop-outs," which are prominent detections in the S2CLS 850{mu}m data but are extremely weak or invisible in the SPIRE bands. Within the 2.98deg^2^ common area of HerMES and S2CLS, we have selected 95 such objects. These very red sources could be dusty starbursts at high redshifts (z>~4-6) because the peak of their cold-dust emission heated by star formation is shifted to the reddest FIR/sub-mm bands. The surface density of 500{mu}m risers is ~8.2deg^-2^ at the >=20mJy level in 500{mu}m, while that of SPIRE drop-outs is ~19.3deg^-2^ at the >=5mJy level in 850{mu}m. Both types of objects could span a wide range of redshifts, however. Using deep radio data in these fields to further select the ones likely at the highest redshifts, we find that the surface density of z>6 candidates is 5.5deg^-2^ among 500{mu}m risers and is 0.8-13.6deg^-2^ among SPIRE drop-outs. If this is correct, the dust-embedded star formation processes in such objects could contribute comparably as Lyman-break galaxies to the global SFR density at z>6.
- ID:
- ivo://CDS.VizieR/J/A+A/587/A160
- Title:
- 3.6um S4G Galactic bars characterization
- Short Name:
- J/A+A/587/A160
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Stellar bars play an essential role in the secular evolution of disk galaxies because they are responsible for the redistribution of matter and angular momentum. Dynamical models predict that bars become stronger and longer in time, while their rotation speed slows down. We use the Spitzer Survey of Stellar Structure in Galaxies (S^4^G) 3.6um imaging to study the properties (length and strength) and fraction of bars at z=0 over a wide range of galaxy masses (M*~=10^8^-10^11^M_{sun}_) and Hubble types (-3<=T<=10). We calculated gravitational forces from the 3.6um images for galaxies with a disk inclination lower than 65{deg}. We used the maximum of the tangential-to-radial force ratio in the bar region (Qb) as a measure of the bar-induced perturbation strength for a sample of ~600 barred galaxies. We also used the maximum of the normalized m=2 Fourier density amplitude (A_2_^max^) and the bar isophotal ellipticity ({epsilon}) to characterize the bar. Bar sizes were estimated i) visually, ii) from ellipse fitting, iii) from the radii of the strongest torque, and iv) from the radii of the largest m=2 Fourier amplitude in the bar region. By combining our force calculations with the HI kinematics from the literature, we estimated the ratio of the halo-to-stellar mass (Mh/M*) within the optical disk and by further using the universal rotation curve models, we obtained a first-order model of the rotation curve decomposition of 1128 disk galaxies. We probe possible sources of uncertainty in our Qb measurements: the assumed scale height and its radial variation, the influence of the spiral arms torques, the effect of non-stellar emission in the bar region, and the dilution of the bar forces by the dark matter halo (our models imply that only ~10% of the disks in our sample are maximal). We find that for early- and intermediate-type disks (-3<=T<5), the relatively modest influence of the dark matter halo leads to a systematic reduction of the mean Qb by about 10-15%, which is of the same order as the uncertainty associated with estimating the vertical scale height. The halo correction on Qb becomes important for later types, implying a reduction of ~20-25% for T=7-10. Whether the halo correction is included or not, the mean Qb shows an increasing trend with T. However, the mean A_2_^max^ decreases for lower mass late-type systems. These opposing trends are most likely related to the reduced force dilution by bulges when moving towards later type galaxies. Nevertheless, when treated separately, both the early- and late-type disk galaxies show a strong positive correlation between Qb and A_2_^max^. For spirals the mean {epsilon}~0.5 is nearly independent of T, but it drops among S0s (~0.2). The Qb and {epsilon} show a relatively tight dependence, with only a slight difference between early and late disks. For spirals, all our bar strength indicators correlate with the bar length (scaled to isophotal size). Late-type bars are longer than previously found in the literature. The bar fraction shows a double-humped distribution in the Hubble sequence (~75% for Sab galaxies), with a local minimum at T=4 (~40%), and it drops for M*<~10^9.5-10^M_{sun}_. If we use bar identification methods based on Fourier decomposition or ellipse fitting instead of the morphological classification, the bar fraction decreases by ~30-50% for late-type systems with T>=5 and correlates with Mh/M*. Our Mh/M* ratios agree well with studies based on weak lensing analysis, abundance matching, and halo occupation distribution methods, under the assumption that the halo inside the optical disk contributes roughly a constant fraction of the total halo mass (~4%). We find possible evidence for the growth of bars within a Hubble time, as (1) bars in early-type galaxies show larger density amplitudes and disk-relative sizes than their intermediate-type counterparts, and (2) long bars are typically strong. We also observe two clearly distinct types of bars, between early- and intermediate-type galaxies (T<5) on one side, and the late-type systems on the other, based on the differences in the bar properties. Most likely this distinction is connected to the higher halo-to-stellar ratio that we observe in later types, which affects the disk stability properties.
- ID:
- ivo://CDS.VizieR/J/ApJ/772/135
- Title:
- 3.6um surface brightness from S4G
- Short Name:
- J/ApJ/772/135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We study the m=1 distortions (lopsidedness) in the stellar components of 167 nearby galaxies that span a wide range of morphologies and luminosities. We confirm the previous findings of (1) a high incidence of lopsidedness in the stellar distributions, (2) increasing lopsidedness as a function of radius out to at least 3.5 exponential scale lengths, and (3) greater lopsidedness, over these radii, for galaxies of later type and lower surface brightness. Additionally, the magnitude of the lopsidedness (1) correlates with the character of the spiral arms (stronger arm patterns occur in galaxies with less lopsidedness), (2) is not correlated with the presence or absence of a bar, or the strength of the bar when one is present, (3) is inversely correlated to the stellar mass fraction, f_*_, within one radial scale length, and (4) correlates directly with f_*_ measured within the radial range over which we measure lopsidedness. We interpret these findings to mean that lopsidedness is a generic feature of galaxies and does not, generally, depend on a rare event, such as a direct accretion of a satellite galaxy onto the disk of the parent galaxy. While lopsidedness may be caused by several phenomena, moderate lopsidedness (<A_1_>_i_+<A_1_>_o_)/2<0.3) is likely to reflect halo asymmetries to which the disk responds or a gravitationally self-generated mode. We hypothesize that the magnitude of the stellar response depends both on how centrally concentrated the stars are with respect to the dark matter and whether there are enough stars in the region of the lopsidedness that self-gravity is dynamically important.
- ID:
- ivo://CDS.VizieR/J/A+A/427/23
- Title:
- 14.3um survey in the Lockman Hole
- Short Name:
- J/A+A/427/23
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the image and catalogue of the 14.3{mu}m hallow survey of 0.55 square degrees in the region of the Lockman Hole (10h 52m 03s, +57{deg} 21' 46", J2000). The data have been analyzed with the recent algorithm by Lari et al. (2001, Cat. <J/MNRAS/325/1173>) conceived to exploit ISO data in an optimal way, especially in the case of shallow surveys with low redundancy. Photometry has been accurately evaluated through extensive simulations and also the absolute calibration has been checked using a set of 21 stars detected at 14.3{mu}m, optical, and near-IR bands.
- ID:
- ivo://CDS.VizieR/J/ApJ/801/127
- Title:
- 3.6um, 4.5um, B and V light curves of NGC 6418
- Short Name:
- J/ApJ/801/127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results from a 15 month campaign of high-cadence (~3 days) mid-infrared Spitzer and optical (B and V) monitoring of the Seyfert 1 galaxy NGC 6418, with the objective of determining the characteristic size of the dusty torus in this active galactic nucleus (AGN). We find that the 3.6 and 4.5{mu}m flux variations lag behind those of the optical continuum by 37.2_-2.2_^+2.4^-days and 47.1_-3.1_^+3.1^-days, respectively. We report a cross-correlation time lag between the 4.5 and 3.6{mu}m flux of 13.9_-0.1_^+0.5^ days. The lags indicate that the dust emitting at 3.6 and 4.5{mu}m is located at a distance ~1-light-month (~0.03pc) from the source of the AGN UV-optical continuum. The reverberation radii are consistent with the inferred lower limit to the sublimation radius for pure graphite grains at 1800K, but smaller by a factor of ~2 than the corresponding lower limit for silicate grains; this is similar to what has been found for near-infrared (K-band) lags in other AGNs. The 3.6 and 4.5{mu}m reverberation radii fall above the K-band {tau}{propto}L^0.5^ size-luminosity relationship by factors <~2.8 and <~3.4, respectively, while the 4.5{mu}m reverberation radius is only 27% larger than the 3.6{mu}m radius. This is broadly consistent with clumpy torus models, in which individual optically thick clouds emit strongly over a broad wavelength range.
- ID:
- ivo://CDS.VizieR/J/AJ/139/2525
- Title:
- UNAM-KIAS catalog of isolated galaxies
- Short Name:
- J/AJ/139/2525
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A new catalog of isolated galaxies from the Sloan Digital Sky Survey Data Release 5 (SDSS DR5) is presented. A total of 1520 isolated galaxies were found in 1.4sr of sky. The selection criteria in this UNAM-KIAS catalog are a variation on the criteria developed by Karachentseva, including full redshift information. Through an image processing pipeline that takes advantage of the high-resolution (~0.4"/pix) and high dynamic range of the SDSS images, a uniform g-band morphological classification for all these galaxies is presented.
- ID:
- ivo://CDS.VizieR/J/MNRAS/416/1135
- Title:
- Unbiased sample of CSS and GPS
- Short Name:
- J/MNRAS/416/1135
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Compact Steep Spectrum (CSS) and Gigahertz Peaked Spectrum (GPS) sources are classes of compact, powerful, extragalactic objects. These sources are thought to be the earliest stages in the evolution of radio galaxies, capturing the ignition (or, in some cases, re-ignition) of the active galactic nucleus. As well as serving as probes of the early stages of large-scale radio sources, these sources are good, stable, amplitude calibrators for radio telescopes. We present an unbiased flux density limited (>1.5Jy at 2.7GHz) catalogue of these objects in the Southern hemisphere, including tabulated data, radio spectra, and where available, optical images and measurements. The catalogue contains 26 sources, consisting of two new candidates and 15 known CSS sources, and nine known GPS sources. We present new Australia Telescope Compact Array (ATCA) data on 10 of these 26 sources, and data on a further 42 sources which were excluded from our final sample. This bright sample will serve as a reference sample for comparison with subsequent faint (mJy level) samples of CSS and GPS candidates currently being compiled.
- ID:
- ivo://CDS.VizieR/J/ApJ/798/54
- Title:
- "Under-massive" black hole candidates
- Short Name:
- J/ApJ/798/54
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Several recent papers have reported on the occurrence of active galactic nuclei (AGNs) containing undermassive black holes relative to a linear scaling relation between black hole mass (M_bh_) and host spheroid stellar mass (M_sph,*_). However, dramatic revisions to the M_bh_-M_sph,*_ and M_bh_-L_sph_ relations, based on samples containing predominantly inactive galaxies, have recently identified a new steeper relation at M_bh_<~(2-10)x10^8^M_{sun}_, roughly corresponding to M_sph,*_<~(0.3-1)x10^11^M_{sun}_. We show that this steeper, quadratic-like M_bh_-M_sph,*_ relation defined by the Sersic galaxies, i.e., galaxies without partially depleted cores, roughly tracks the apparent offset of the AGN having 10^5^<~M_bh_/M_{sun}_<~0.5x10^8^. That is, these AGNs are not randomly offset with low black hole masses, but also follow a steeper (nonlinear) relation. As noted by Busch et al. (2014, J/A+A/561/A140), confirmation or rejection of a possible AGN offset from the steeper M_bh_-M _sph,*_ relation defined by the Sersic galaxies will benefit from improved stellar mass-to-light ratios for the spheroids hosting these AGNs. Several implications for formation theories are noted. Furthermore, reasons for possible under- and overmassive black holes, the potential existence of intermediate mass black holes (<10^5^M_{sun}_), and the new steep (black hole)-(nuclear star cluster) relation, M_bh_{propto}M_nc_^2.7+/-0.7^, are also discussed.
- ID:
- ivo://CDS.VizieR/J/ApJS/105/343
- Title:
- Universidad Complutense de Madrid list 2
- Short Name:
- J/ApJS/105/343
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A low dispersion objective-prism survey for low-redshift emission-line galaxies (ELGs) is being carried out by the University Complutense de Madrid with the Schmidt telescope at the German-Spanish Observatory of Calar Alto (Almeria, Spain). A 4{deg} full aperture prism, which provides a dispersion of 1950{AA}/mm, and IIIa-F emulsion combination has been used to search for ELGs selected by the presence of H{alpha} emission in their spectra. A compilation of descriptions and positions, along with finding charts, is presented for 103 emission-line objects. This is the second list, which contains objects located in a region of the sky covering 201.4{deg}^2^ in seven fields near {alpha}=15h and {delta}=25{deg}.
