- ID:
- ivo://CDS.VizieR/J/A+A/561/A148
- Title:
- Mass Distribution of Infrared Dark Clouds
- Short Name:
- J/A+A/561/A148
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present an analysis of the dust continuum emission at 870um in order to investigate the mass distribution of clumps within infrared dark clouds (IRDCs). We map six IRDCs with the Large APEX BOlometer CAmera (LABOCA) at APEX, reaching an rms noise level of 28-44mJy/beam. The dust continuum emission coming from these IRDCs was decomposed by using two automated algorithms, Gaussclumps and Clumpfind. We identify 510 and 352 sources with Gaussclumps and Clumpfind, respectively, and estimate masses and other physical properties assuming a uniform dust temperature. The mass ranges are 6-2692M_{sun}_(Gaussclumps) and 7-4254M_{sun} (Clumpfind) and the ranges in effective radius are around 0.10-0.74pc (Gaussclumps) and 0.16-0.99pc (Clumpfind). The mass distribution, independent of the decomposition method used, is fitted by a power law, dN/dM{prop.to}M^alpha^, with an index (alpha) of -1.60+/-0.06.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/404/223
- Title:
- 2MASS IR star clusters in the Galaxy
- Short Name:
- J/A+A/404/223
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We carried out a survey of infrared star clusters and stellar groups on the 2MASS J, H and Ks all-sky release Atlas in the Northern and Equatorial Milky Way (350{deg},l<360{deg}, 0{deg}<l<230{deg}). The search in this zone complements that in the Southern Milky Way (Dutra et al., 2003, Cat. <J/A+A/400/533>). The method concentrates efforts on the directions of known optical and radio nebulae. The present study provides 167 new infrared clusters, stellar groups and candidates. Combining the two studies for the whole Milky Way, 346 infrared clusters, stellar groups and candidates were discovered, whereas 315 objects were previously known. They constitute an important new sample for future detailed studies.
- ID:
- ivo://CDS.VizieR/J/ApJ/762/83
- Title:
- Massive early-type galaxies in K-band
- Short Name:
- J/ApJ/762/83
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use high-resolution K-band VLT/HAWK-I imaging over 0.25deg^2^ to study the structural evolution of massive early-type galaxies since z~2. Mass-selected samples, complete down to log(M/M_{sun}_)~10.7 such that "typical" (L*) galaxies are included at all redshifts, are drawn from pre-existing photometric redshift surveys. We then separate the samples into different redshift slices and classify them as late- or early-type galaxies on the basis of their specific star formation rate. Axis-ratio measurements for the ~400 early-type galaxies in the redshift range 0.6<z<1.8 are accurate to 0.1 or better. The projected axis-ratio distributions are then compared with lower redshift samples. We find strong evidence for evolution of the population properties: early-type galaxies at z>1 are, on average, flatter than at z<1 and the median projected axis ratio at a fixed mass decreases with redshift. However, we also find that at all epochs z<~2, the most massive early-type galaxies (log(M/M_{sun}_)>11.3) are the roundest, with a pronounced lack of galaxies that are flat in projection. Merging is a plausible mechanism that can explain both results: at all epochs, merging is required for early-type galaxies to grow beyond log(M/M_{sun}_)~11.3, and all early types over time gradually and partially lose their disk-like characteristics.
- ID:
- ivo://CDS.VizieR/J/ApJ/719/1104
- Title:
- Massive star forming complexes in GLIMPSE
- Short Name:
- J/ApJ/719/1104
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We examine the 13 most luminous sources in the WMAP free-free map using the Spitzer GLIMPSE and Midcourse Space Experiment surveys to identify massive star formation complexes, emitting one-third of the Galactic free-free luminosity. We identify star-forming complexes (SFCs) by a combination of bubble morphology in 8um emission and radio recombination line radial velocities. We find 40 SFCs associated with our WMAP sources and determine unique distances up to 31. We interpret the bubbles as evidence for radial expansion. The radial velocity distribution for each source allows us to measure the intrinsic speed of a complex's expansion. This speed is consistent with the size and age of the bubbles. The high free-free luminosities, combined with negligible synchrotron emission, demonstrate that the bubbles are not driven by supernovae. The kinetic energy of the largest bubbles is a substantial fraction of that measured in the older superbubbles found by Heiles. We find that the energy injected into the interstellar medium by our bubbles is similar to that required to maintain turbulent motion in the gas disk inside 8kpc. We report a number of new SFCs powered by massive (M_*_>10^4^M_{sun}_) star clusters. We measure the scale height of the Galactic O stars to be h_*_=35+/-5pc. We determine an empirical relationship between the 8um and free-free emission of the form F_8um_{propto}F^2^_ff_. Finally, we find that the bubble geometry is more consistent with a spherical shell rather than a flattened disk.
- ID:
- ivo://CDS.VizieR/J/AJ/138/1508
- Title:
- 2MASS large-amplitude variable stars
- Short Name:
- J/AJ/138/1508
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of variable stars in the near-infrared wavelength detected with overlapping regions of the Two Micron All Sky Survey public images, and discuss their properties. The investigated region is in the direction of the Galactic center (-30{deg}<~l<~20, |b|<~20), which covers the entire bulge. We have detected 136 variable stars, of which six are already known and 118 are distributed in the |b|<5{deg} region. Additionally, 84 variable stars have optical counterparts in Digitized Sky Survey images. The three diagrams (color-magnitude, light variance, and color-color diagrams) indicate that most of the detected variable stars should be large-amplitude and long-period variables such as Mira variables or OH/IR stars. The number density distribution of the detected variable stars implies that they trace the bar structure of the Galactic bulge.
- ID:
- ivo://CDS.VizieR/J/A+A/403/943
- Title:
- Mass-loss rates of galactic AGB stars
- Short Name:
- J/A+A/403/943
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We are using the 2002 data-release from the Japanese space experiment IRTS to investigate the spatial distribution of galactic mass-losing (>2x10^-8_M_{sun}_/yr) AGB stars and the relative contribution of C-rich and O-rich ones to the replenishment of the ISM. Our sample contains 126 C-rich and 563 O-rich sources which are sorted on the basis of the molecular bands observed in the range 1.4-4.0{mu}m, and for which we estimate distances and mass loss rates from near-infrared photometry (K and L'). There is a clear dependence on galactocentric distance, with O-rich sources outnumbering C-rich ones for {tau}_GC_<8kpc, and the reverse for {tau}_GC_>10kpc. The contribution to the replenishment of the ISM by O-rich AGB stars relative to C-rich ones follows the same trend. Although they are rare (~10% in our sample), sources with 10^-6^M_{sun}_/yr<dM/dt<10^-5^M_{sun}_/yr dominate the replenishment of the ISM by contributing to ~50% of the total of the complete sample. We find 2 carbon stars at more than 1kpc from the Galactic Plane, that probably belong to the halo of our Galaxy.
- ID:
- ivo://CDS.VizieR/J/ApJ/476/311
- Title:
- 2MASS M-dwarf discoveries
- Short Name:
- J/ApJ/476/311
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have obtained follow-up spectroscopy of eight late dwarf candidates discovered in a 105deg^2^ area observed with the 2MASS (2 Micron All-Sky Survey) Prototype Camera during test runs between 1992 and 1994. These objects were chosen because of their red infrared colors (e.g., J-Ks>=1.10) and/or red OIR colors (e.g., R-Ks>=6.00). All eight are late M dwarfs, six of which have spectral types later than van Biesbroeck 8 (type M7 V). Despite the fact that we have only followed up a fraction of the reddest sources discovered, the number of known M dwarfs of type M7 and cooler has been increased by 30%. Extrapolation of these results alone shows that over 2000 dwarfs of similar spectral type and with Ks<=14.0 will be imaged by 2MASS over the entire sky. One of these new discoveries is astonishingly cool and has a tentative type of >=M10V. This dwarf, one of the least luminous objects yet discovered, could itself be a high-mass brown dwarf, thus providing another empirical data point in a regime where few such objects are now recognized. Only the substellar suspect GD 165 B and the bona fide brown dwarf GL 229 B, both discovered as companions to known stars, are cooler. Thus, this 2MASS discovery becomes the coolest isolated object so far identified.
- ID:
- ivo://CDS.VizieR/J/other/NewA/11.27
- Title:
- 2MASS observation of BL Lac objects
- Short Name:
- J/other/NewA/11.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 2MASS observations of known BL Lac objects are presented in this paper. The 2MASS associations for 511 BL Lac objects are identified. From the 2MASS near infrared two-color diagram it is seen that majority (about 70%) of objects are lying alone with or very close to the power law distribution implying that there is no need to invoke any significant radiation mechanism additional to a power law continuum for those sources. However, many sources (about 30%) are still located very close to the blackbody distribution indicative of the possible contributions from the host galaxies. In addition, the average spectral index derived for the near infrared region is 0.66+/-0.34 that is rather smaller than that from the previous results indicative of the possible influence from the host galaxies and/or from the lack or weakness of the radio emissions from most sources newly discovered by recent X-ray missions.
- ID:
- ivo://CDS.VizieR/J/other/NewA/16.503
- Title:
- 2MASS observation of BL Lac objects II.
- Short Name:
- J/other/NewA/16.
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this paper, we have searched for the Two Micron All Sky Survey (2MASS, Cat. II/246) counterparts of 1434 BL Lacs. 833 of 1434 BL Lacs (58%) have spatially coincident 2MASS counterparts. Fermi-detected BL Lacs (FBLs) have a much higher 2MASS detection rate than non-Fermi-detected BL Lacs (non-FBLs) (95% vs 49%).
- ID:
- ivo://CDS.VizieR/J/AJ/131/1942
- Title:
- 2MASS observations of IRAS 1Jy ULIRGs
- Short Name:
- J/AJ/131/1942
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Two Micron All Sky Survey observation of the IRAS 1Jy sample of ultraluminous infrared galaxies (ULIRGs) is presented in this paper. Together with the IRAS photometric data, the properties and energy sources of the IRAS 1Jy sample of ULIRGs in the near- and far-infrared are discussed.
