- ID:
- ivo://CDS.VizieR/J/A+A/486/73
- Title:
- AMIGA VII. FIR and radio study
- Short Name:
- J/A+A/486/73
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper is part of a series involving the AMIGA project (Analysis of the Interstellar Medium of Isolated GAlaxies). This project provides a statistically-significant sample of the most isolated galaxies in the northern sky. We present a study of the nuclear activity in a well-defined sample of the most isolated galaxies (total sample: n=1050, complete subsample: n=719) in the local Universe traced by their far-infrared (FIR) and radio continuum emission. We use the well-known radio continuum-FIR correlation to select radio-excess galaxies that are candidates to host an active galactic nucleus (AGN), as well as the FIR colours to find obscured AGN-candidates. We also used the existing information on nuclear activity in the Veron-Cetty catalogue and in the NASA Extragalactic Database. A final catalogue of AGN-candidate galaxies has been produced that will provide a baseline for studies on the dependence of activity on the environment. Our sample is mostly radio quiet, consistent with its high content of late-type galaxies. At most ~1.5% of the galaxies show a radio excess with respect to the radio-FIR correlation, and this fraction even goes down to less than 0.8% after rejection of back/foreground sources using FIRST. We find that the fraction of FIR colour selected AGN-candidates is ~28% with a lower limit of ~7%. Our final catalogue contains 89 AGN candidates and is publicly available on the AMIGA web page (http://www.iaa.csic.es/AMIGA.html).
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJS/248/18
- Title:
- 44 and 95GHz observations of class I methanol masers
- Short Name:
- J/ApJS/248/18
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report a simultaneous 44 and 95GHz class I methanol maser survey toward 144 sources from the 95GHz class I methanol maser catalog. The observations were made with the three telescopes of the Korean very long baseline interferometry network operating in single-dish mode. The detection rates are 89% at 44GHz and 77% at 95GHz. There are 106 new discoveries at 44GHz. Comparing the previous 95GHz detections with new observations of the same transitions made using the Purple Mountain Observatory 13.7m radio telescope shows no clear evidence of variability on a timescale of six years. Emission from the 44 and 95GHz transitions shows strong correlations in peak velocity, peak flux density, and integrated flux density, indicating that they are likely cospatial. We found that the peak flux density ratio S_pk,95_/S_pk,44_ decreases as the 44GHz peak flux density increases. We found that some class I methanol masers in our sample might be associated with infrared dark clouds, while others are associated with HII regions, indicating that some sources occur at an early stage of high-mass star formation, while others are located toward more evolved sources.
- ID:
- ivo://CDS.VizieR/J/A+A/490/213
- Title:
- 1.4 and 3.4mm interferometry of W3 IRS5
- Short Name:
- J/A+A/490/213
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of PdBI 1.4 and 3.4mm interferometric observations of the high-mass star-forming region W3 IRS5 in the AB configurations. From the continuum maps we identified five individual sources with counterparts in the NIR, MIR or radio (Q-band), except for one source that is a new identification. Three of the sources are within the inner 2100AU, where the protostellar number density exceeds 10^6^ protostars pc^-3^ assuming spherical symmetry. Lower limits for the circumstellar masses of the sources range from ~0.3 to ~40M_{sun}_ although they were strongly affected by the spatial filtering of the interferometer. We mapped the SiO(2-1), SiO(5-4), SO2(22-22), and SO2(8-9) molecular transitions. We identify five molecular outflows in SiO, two of them nearly in the line of sight direction. The SO2 velocity structure indicates a rotating, bound system, and we find tentative signatures of converging flows as predicted by the gravoturbulent star formation and converging flow theories. The obtained data strongly indicate that the clustered environment has a major influence on the formation of high-mass stars; however, our data do not clearly allow us to distinguish whether the ongoing star-forming process follows a monolithic collapse or a competitive accretion mechanism.
- ID:
- ivo://CDS.VizieR/J/ApJ/724/1336
- Title:
- An extragalactic ^12^CO J=3-2 survey
- Short Name:
- J/ApJ/724/1336
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present results of a ^12^COJ=3-2 survey of 125 nearby galaxies obtained with the 10m Heinrich Hertz Telescope, with the aim to characterize the properties of warm and dense molecular gas in a large variety of environments. With an angular resolution of 22", ^12^CO3-2 emission was detected in 114 targets. Based on 61 galaxies observed with equal beam sizes the ^12^CO3-2/1-0 integrated line intensity ratio R_31_ is found to vary from 0.2 to 1.9, with an average value of 0.81. No correlations are found for R_31_ to Hubble-type and far-infrared luminosity. Possible indications for a correlation with inclination angle and the 60um/100um color temperature of the dust are not significant. Higher R_31_ ratios than in "normal" galaxies, hinting at enhanced molecular excitation, may be found in galaxies hosting active galactic nuclei. Even higher average values are determined for galaxies with bars or starbursts, the latter being identified by the ratio of infrared luminosity versus isophotal area, log [(L_FIR_/L_{sun}_)/(D^2^_25_/kpc^2^)]>7.25. (U)LIRGs are found to have the highest averaged R_31_ value. This may be a consequence of particularly vigorous star formation activity, triggered by galaxy interaction and merger events.
- ID:
- ivo://CDS.VizieR/J/ApJ/727/83
- Title:
- A panchromatic study of BLAST counterparts
- Short Name:
- J/ApJ/727/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carry out a multi-wavelength study of individual galaxies detected by the Balloon-borne Large Aperture Submillimeter Telescope (BLAST) and identified at other wavelengths, using data spanning the radio to the ultraviolet (UV). We develop a Monte Carlo method to account for flux boosting, source blending, and correlations among bands, which we use to derive deboosted far-infrared (FIR) luminosities for our sample. We estimate total star-formation rates (SFRs) for BLAST counterparts with z<=0.9 by combining their FIR and UV luminosities. We assess that about 20% of the galaxies in our sample show indication of a type 1 active galactic nucleus, but their submillimeter emission is mainly due to star formation in the host galaxy. We compute stellar masses for a subset of 92 BLAST counterparts; these are relatively massive objects, with a median mass of ~10^11^M_{sun}_, which seem to link the 24um and Submillimetre Common-User Bolometer Array (SCUBA) populations, in terms of both stellar mass and star formation activity.
- ID:
- ivo://CDS.VizieR/J/A+A/608/A102
- Title:
- APEX CO and HI observations of Lupus I
- Short Name:
- J/A+A/608/A102
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Lupus I cloud is found between the Upper Scorpius (USco) and Upper Centaurus-Lupus (UCL) subgroups of the Scorpius-Centaurus OB association, where the expanding USco HI shell appears to interact with a bubble currently driven by the winds of the remaining B stars of UCL. Aims. We investigate whether the Lupus I molecular could have formed in a colliding flow, and in particular, how the kinematics of the cloud might have been influenced by the larger scale gas dynamics. We performed APEX ^13^CO(2-1)and C^18^O(2-1) line observations of three distinct parts of Lupus I that provide kinematic information on the cloud at high angular and spectral resolution. We compare those results to the atomic hydrogen data from the GASS HI survey and our dust emission results presented in the previous paper. Based on the velocity information, we present a geometric model for the interaction zone between the USco shell and the UCL wind bubble. We present evidence that the molecular gas of Lupus Iis tightly linked to the atomic material of the USco shell. The CO emission in Lupus Iis found mainly at velocities between v_LSR_=3-6km/s, which is in the same range as the HI velocities. Thus, the molecular cloud is co-moving with the expanding USco atomic HI shell. The gas in the cloud shows a complex kinematic structure with several line-of-sight components that overlay each other. The nonthermal velocity dispersion is in the transonic regime in all parts of the cloud and could be injected by external compression. Our observations and the derived geometric model agree with a scenario in which Lupus Iis located in the interaction zone between the USco shell and the UCL wind bubble. The kinematics observations are consistent with a scenario in which the Lupus Icloud formed via shell instabilities. The particular location of Lupus I between USco and UCL suggests that counterpressure from the UCL wind bubble and pre-existing density enhancements, perhaps left over from the gas stream that formed the stellar subgroups, may have played a role in its formation.
- ID:
- ivo://CDS.VizieR/J/MNRAS/505/6051
- Title:
- Arecibo sample variability properties
- Short Name:
- J/MNRAS/505/6051
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- We present the results of a near-infrared (NIR) monitoring program carried out between 1999 and 2005 to determine the variability properties of the `Arecibo sample of OH/IR stars'. The sample consists of 385 IRAS-selected Asymptotic Giant Branch (AGB) candidates, for which their O-rich chemistry has been proven by the detection of 1612 MHz OH maser emission. The monitoring data was complemented by data collected from public optical and NIR surveys. We fitted the light curves obtained in the optical and NIR bands with a model using an asymmetric cosine function, and derived a period for 345 sources ~90% of the sample). Based on their variability properties, most of the Arecibo sources are classified as long-period large-amplitude variable stars (LPLAV), 4% as (candidate) post-AGB stars, and 3% remain unclassified although they are likely post-AGB stars or highly obscured AGB stars. The period distribution of the LPLAVs peaks at ~400d, with periods between 300 and 800d for most of the sources, and has a long tail up to ~2100d. Typically, the amplitudes are between 1 and 3 mag in the NIR and between 2 and 6 mag in the optical. We find correlations between periods and amplitudes, with larger amplitudes associated to longer periods, as well as between the period and the infrared colours, with the longer periods linked to the redder sources. Among the post-AGB stars, the light curve of IRAS 19566+3423 was exceptional, showing a large systematic increase (>0.4mag/yr) in K-band brightness over 7 years.
- ID:
- ivo://CDS.VizieR/J/ApJ/715/506
- Title:
- Aromatic inventory of the local volume
- Short Name:
- J/ApJ/715/506
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using infrared photometry from the Spitzer Space Telescope, we perform the first inventory of aromatic feature emission (also commonly referred to as polycyclic aromatic hydrocarbon emission) for a statistically complete sample of star-forming galaxies in the local volume. The photometric methodology involved is calibrated and demonstrated to recover the aromatic fraction of the Infrared Array Camera 8um flux with a standard deviation of 6% for a training set of 40 SINGS galaxies (ranging from stellar to dust dominated; Kennicutt et al. 2003PASP..115..928K) with both suitable mid-infrared Spitzer Infrared Spectrograph spectra and equivalent photometry. A potential factor of 2 improvement could be realized with suitable 5.5um and 10um photometry, such as what may be provided in the future by the James Webb Space Telescope. The resulting technique is then applied to mid-infrared photometry for the 258 galaxies from the Local Volume Legacy (LVL; Dale et al. 2009, Cat. J/ApJ/703/517) survey, a large sample dominated in number by low-luminosity dwarf galaxies for which obtaining comparable mid-infrared spectroscopy is not feasible. Using oxygen abundances compiled from the literature for 129 of the 258 LVL galaxies, we find a correlation between metallicity and the aromatic-to-total infrared emission ratio but not the aromatic-to-total 8um dust emission ratio. A possible explanation is that metallicity plays a role in the abundance of aromatic molecules relative to the total dust content, but other factors, such as star formation and/or the local radiation field, affect the excitation of those molecules.
- ID:
- ivo://CDS.VizieR/J/A+A/562/A121
- Title:
- ARRAKIS: Atlas of Resonance Rings as Known In S4G
- Short Name:
- J/A+A/562/A121
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Resonance rings and pseudorings (here collectively called "rings") are thought to be related to the gathering of material near dynamical resonances caused by non-axisymmetries in galaxy discs. Therefore, they are the consequence of secular evolution processes that redistribute material and angular momentum in discs. Their study may give clues on the formation and growth of bars and other disc non-axisymmetries. Our aims are to produce a Catalogue and an Atlas of the rings detected in the Spitzer Survey of Stellar Structure in Galaxies (S4G) and to conduct a statistical study of the data in the Catalogue. We traced the contours of rings previously identified by Buta et al. (in preparation) and fitted them with ellipses. We found the orientation of bars by studying the galaxy ellipse fits from S4G's Pipeline4. We used the galaxy orientation data obtained by S4G's Pipeline 4 to obtain intrinsic ellipticities and orientations of rings and the bars. ARRAKIS contains data on 724 ringed galaxies in the S4G. The frequency of resonance rings in the S4G is of 16+/-1% and 35+/-1% for outer and inner features, respectively. Outer rings are mostly found in Hubble stages -1<=T<=4. Inner rings are found in a broad distribution that covers the range -1<=T<=7. We confirm that outer rings have two preferred orientations, namely parallel and perpendicular to the bar. We confirm a tendency for inner rings to be oriented parallel to the bar, but we report the existence of a significant fraction (maybe as large as 50%) of inner features that have random orientations with respect to the bar. These misaligned inner rings are mostly found in late-type galaxies (T>=4). We find that the fraction of barred galaxies hosting outer (inner) rings is ~1.7 times (~1.3 times) that in unbarred galaxies. We confirm several results from previous surveys, as well as predictions from simulations of resonant rings and/or from manifold flux tube theory. We report that a significant fraction of inner rings in late-type galaxies have a random orientation with respect to the bar. This may be due to spiral modes decoupled from the bar dominating the Fourier amplitude spectrum at the radius of the inner ring. The fact that rings are only mildly favoured by bars suggests that those in unbarred galaxies either formed due to weak departures from the axisymmetry of the galactic potential or that they are born because of bars that have been destroyed after the ring formation.
- ID:
- ivo://CDS.VizieR/J/A+A/646/A141
- Title:
- A source catalog for the LMC
- Short Name:
- J/A+A/646/A141
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a clean, magnitude-limited (IRAC1 or WISE1<=15.0mag) multiwavelength source catalog for the Large Magellanic Cloud (LMC). The catalog was built by crossmatching (1'') and deblending (3'') between the source list of Spitzer Enhanced Imaging Products (SEIP) and Gaia Data Release 2 (DR2), with strict constraints on the Gaia astrometric solution in order to remove the foreground contamination. It is estimated that about 99.5% of the targets in our catalog are most likely genuine members of the LMC. The catalog contains 197004 targets in 52 different bands, including two ultraviolet, 21 optical, and 29 infrared bands. Additional information about radial velocities and spectral and photometric classifications were collected from the literature. We compare our sample with the sample from Gaia DR2 (2018A&A...616A...1G, Cat. I/345), indicating that the bright end of our sample is mostly comprised of blue helium-burning stars (BHeBs) and red HeBs with inevitable contamination of main sequence stars at the blue end. After applying modified magnitude and color cuts based on previous studies, we identified and ranked 2974 red supergiant, 508 yellow supergiant, and 4786 blue supergiant candidates in the LMC in six color-magnitude diagrams (CMDs). The comparison between the CMDs from the two catalogs of the LMC and Small Magellanic Cloud (SMC) indicates that the most distinct difference appears at the bright red end of the optical and near-infrared CMDs, where the cool evolved stars (e.g., red supergiant stars (RSGs), asymptotic giant branch stars, and red giant stars) are located, which is likely due to the effect of metallicity and star formation history. A further quantitative comparison of colors of massive star candidates in equal absolute magnitude bins suggests that there is essentially no difference for the BSG candidates, but a large discrepancy for the RSG candidates since LMC targets are redder than the SMC ones, which may be due to the combined effect of metallicity on both spectral type and mass-loss rate as well as the age effect. The effective temperatures (Teff) of massive star populations are also derived from reddening-free color of (J-K_S_0. The Teff ranges are 3500<Teff<5000K for an RSG population, 5000<Teff<8000K for a YSG population, and Teff>8000K for a BSG population, with larger uncertainties toward the hotter stars.