- ID:
- ivo://CDS.VizieR/II/241
- Title:
- 2MASS Catalog Incremental Data Release
- Short Name:
- II/241
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Two Micron All Sky Survey (2MASS) project is designed to close the gap between our current technical capability and our knowledge of the near-infrared sky. In addition to providing a context for the interpretation of results obtained at infrared and other wavelengths, 2MASS will provide direct answers to immediate questions on the large-scale structure of the Milky Way and the Local Universe. To achieve these goals, 2MASS is uniformly scanning the entire sky in three near-infrared bands to detect and characterize point sources brighter than about 1 mJy in each band, with signal-to-noise ratio (SNR) greater than 10, using a pixel size of 2.0". This will achieve an 80,000-fold improvement in sensitivity relative to earlier surveys. 2MASS uses two new, highly-automated 1.3-m telescopes, one at Mt. Hopkins, AZ, and one at CTIO, Chile. Each telescope is equipped with a three-channel camera, each channel consisting of a 256x256 array of HgCdTe detectors, capable of observing the sky simultaneously at J (1.25 {mu}m), H (1.65 {mu}m), and Ks (2.17 {mu}m), to a 3{sigma} limiting sensivity of 17.1, 16.4 and 1.3mag in thge three bands. The 2MASS arrays image the sky while the telescopes scan smoothly in declination at a rate of ~1' per second. The 2MASS data "tiles" are 6{deg} long in the declination direction and one camera frame (8.5') wide. The camera field-of-view shifts by ~1/6 of a frame in declination from frame-to-frame. The camera images each point on the sky six times for a total integration time of 7.8 s, with sub-pixel "dithering", which improves the ultimate spatial resolution of the final Atlas Images. The University of Massachusetts (UMass) is responsible for the overall management of the project, and for developing the infrared cameras and on-site computing systems at both facilities. The Infrared Processing and Analysis Center (IPAC) is responsible for all data processing through the Production Pipeline, and construction and distribution of the data products. The 2MASS project involves the participation of members of the Science Team from several different institutions. The 2MASS project is funding by the National Aeronautics and Space Administration (NASA) and the National Science Foundation (NSF).
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Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/127/501
- Title:
- 2MASS counterparts for OH/IR stars
- Short Name:
- J/AJ/127/501
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The positions of the IRAS counterparts to the 420 OH/IR stars in the Arecibo sky (0{deg}<{delta}<+38{deg}) are usually accurate to better than 10". But every star has recently been observed by the Two Micron All Sky Survey (2MASS, <II/246>), which provides 0.2" quality positions, while those with |b|<=4.5{deg} have also been observed by the Midcourse Space Experiment (MSX, <V/114>), which provides ~2" quality positions. We use the MSX and/or IRAS coordinates to guide us to 2MASS counterparts for the 134 Arecibo OH/IR stars with images in the second release of the 2MASS Point Source Catalog. An unexpected by-product of having the J-H versus H-K_s_ plot generated from the 2MASS fluxes is the realization that most (~85%) of the redder OH/IR stars have detached circumstellar shells. We identify five objects that probably, by contrast, have "normal" shells, and we confirm the status of AU Vul as a protoplanetary nebula.
- 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.
- 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/A+A/617/A66
- Title:
- Massive eclipsing SB2 in Arches cluster spectra
- Short Name:
- J/A+A/617/A66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have carried out a spectroscopic variability survey of some of the most massive stars in the Arches cluster, using K-band observations obtained with SINFONI on the VLT. One target, F2, exhibits substantial changes in radial velocity; in combination with new KMOS and archival SINFONI spectra, its primary component is found to undergo radial velocity variation with a period of 10.483+/-0.002d and an amplitude of ~350km/s. A secondary radial velocity curve is also marginally detectable. We reanalyse archival NAOS-CONICA photometric survey data in combination with our radial velocity results to confirm this object as an eclipsing SB2 system, and the first binary identified in the Arches. We model it as consisting of an 82+/-12M_{sun}_ WN8-9h primary and a 60+/-8M_{sun}_ O5-6 Ia+ secondary, and as having a slightly eccentric orbit, implying an evolutionary stage prior to strong binary interaction. As one of four X-ray bright Arches sources previously proposed as colliding-wind massive binaries, it may be only the first of several binaries to be discovered in this cluster, presenting potential challenges to recent models for the Arches' age and composition. It also appears to be one of the most massive binaries detected to date; the primary's calculated initial mass of >~120M_{sun}_ would arguably make this the most massive binary known in the Galaxy.
- 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/ApJS/247/17
- Title:
- Massive stars in APOGEE2 Survey. III.
- Short Name:
- J/ApJS/247/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have applied the semi-empirical spectral analysis, developed by the Sloan Digital Sky Survey (SDSS)-IV/Apache Point Observatory Galactic Evolution Experiment 2 (APOGEE2) Massive Star Team, to a large sample of new O- and B-type stars identified along the Sagittarius spiral arm, in the direction of the southern star clusters NGC3603 and NGC3576. We obtained H-band spectra for 265 point sources, using the APOGEE2-S spectrograph at the du Pont Telescope at the Las Campanas Observatory. We analyzed the associated spectral features deriving spectral types, as well as the massive star distribution along the line of sight. From a total of 265 science targets, 95 are classified as mid- to late-O-type stars (for which only 10 O-type stars are previously known in the literature), 38 are found to be early- to mid-B-type stars, and 32 are classified as either yellow or blue supergiants, completing a total of 165 massive stars.
- ID:
- ivo://CDS.VizieR/J/ApJ/873/66
- Title:
- Massive stars in SDSS/APOGEE-2. II. W3-W4-W5
- Short Name:
- J/ApJ/873/66
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work, we have applied a semi-empirical spectral classification method for OB-stars using the APOGEE spectrograph to a sample of candidates in the W3-W4-W5 (W345) complexes. These massive star-forming regions span over 200pc across the Perseus arm and have a notorious population of massive stars, from which a large fraction are members of various embedded and young open clusters. From 288 APOGEE spectra showing H-band spectral features typical of O- and B-type sources, 46 probably correspond to previously unknown O-type stars. Therefore, we confirm that Br11-Br13 together with HeII {lambda}16923 (7-12) and HeII {lambda}15723 (7-13) lines contained in the APOGEE spectral bands are useful in providing spectral classification down to one spectral sub-class for massive stars in regions as distant as d~2kpc. The large number of newly found O-type stars as well as the numerous intermediate-mass population confirm that W345 is a very efficient massive star factory, with an integral stellar population probably amounting several thousand solar masses.
- 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.
