- ID:
- ivo://CDS.VizieR/J/A+A/620/A55
- Title:
- Magnetic flaring from PMS stars spectra
- Short Name:
- J/A+A/620/A55
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Flares from the Sun and other stars are most prominently observed in the soft X-ray band. Most of the radiated energy, however, is released at optical/UV wavelengths. In spite of decades of investigation, the physics of flares is not fully understood. Even less is known about the powerful flares routinely observed from pre-main sequence stars, which might significantly influence the evolution of circumstellar disks. Observations of the NGC2264 star forming region were obtained in Dec. 2011, simultaneously with three telescopes, Chandra (X-rays), CoRoT (optical), and Spitzer (mIR), as part of the "Coordinated Synoptic Investigation of NGC2264" (CSI-NGC2264). Shorter Chandra and CoRoT observations were also obtained in March 2008. We analyzed the lightcurves to detect X-ray flares with an optical and/or mIR counterpart. Basic flare properties from the three datasets, such as emitted energies and peak luminosities, were then compared to constrain the spectral energy distribution of the flaring emission and the physical conditions of the emitting regions. Flares from stars with and without circumstellar disks were also compared to establish any difference that might be attributed to the presence of disks. Seventy-eight X-ray flares with an optical and/or mIR counterpart were detected. Their optical emission is found to correlate well with, and to be significantly larger than, the X-ray emission. The slopes of the correlations suggest that the difference becomes smaller for the most powerful flares. The mIR flare emission seems to be strongly affected by the presence of a circumstellar disk: flares from stars with disks have a stronger mIR emission with respect to stars without disks. This might be attributed to the reprocessing of the optical (and X-ray) flare emission by the inner circumstellar disk, providing evidence for flare-induced disk heating.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/741/68
- Title:
- Main Belt asteroids with WISE/NEOWISE. I.
- Short Name:
- J/ApJ/741/68
- Date:
- 01 Feb 2022 07:05:56
- Publisher:
- CDS
- Description:
- We present initial results from the Wide-field Infrared Survey Explorer (WISE), a four-band all-sky thermal infrared survey that produces data well suited for measuring the physical properties of asteroids, and the NEOWISE enhancement to the WISE mission allowing for detailed study of solar system objects. Using a NEATM thermal model fitting routine, we compute diameters for over 100000 Main Belt asteroids (MBAs) from their IR thermal flux, with errors better than 10%. We then incorporate literature values of visible measurements (in the form of the H absolute magnitude) to determine albedos. Using these data we investigate the albedo and diameter distributions of the Main Belt. As observed previously, we find a change in the average albedo when comparing the inner, middle, and outer portions of the Main Belt. We also confirm that the albedo distribution of each region is strongly bimodal. We observe groupings of objects with similar albedos in regions of the Main Belt associated with dynamical breakup families. Asteroid families typically show a characteristic albedo for all members, but there are notable exceptions to this.
- ID:
- ivo://CDS.VizieR/J/ApJ/606/664
- Title:
- MAMBO sources near NTT Deep Field
- Short Name:
- J/ApJ/606/664
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We discuss identifications for 18 sources from our Max-Planck- Millimeter-Bolometer (MAMBO) 1.2mm survey of the region surrounding the NTT Deep Field. We have obtained accurate positions from Very Large Array 1.4GHz interferometry, and in a few cases IRAM millimeter interferometry, and have also made deep BVRIzJK imaging at ESO.
- ID:
- ivo://CDS.VizieR/J/ApJ/903/52
- Title:
- MaNGA; parameters of 668 galaxies
- Short Name:
- J/ApJ/903/52
- Date:
- 15 Mar 2022
- Publisher:
- CDS
- Description:
- The search for new global scaling relations linking the physical properties of galaxies has a fundamental interest. Furthermore, their recovery from spatially resolved relations has been in the spotlight of integral field spectroscopy (IFS). In this study, we investigate the existence of global and local relations between stellar age (Age*) and gas-phase metallicity (Zg). To this aim, we analyze IFS data for a sample of 736 star-forming disk galaxies from the MaNGA survey. We report a positive correlation between the global Zg and D(4000) (an indicator of stellar age), with a slope that decreases with increasing galaxy mass. Locally, a similar trend is found when analyzing the Zg and D(4000) of the star-forming regions, as well as the residuals resulting from removing the radial gradients of both parameters. The local laws have systematically smaller slopes than the global one. We ascribe this difference to random errors that cause the true slope of the Age*-Zg relation to be systematically underestimated when performing a least-squares fitting. The explored relation is intimately linked with the already known relation between gas metallicity and star formation rate at fixed mass, both presenting a common physical origin.
- ID:
- ivo://CDS.VizieR/J/A+A/614/A116
- Title:
- Masgomas-6 near-IR spectra
- Short Name:
- J/A+A/614/A116
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent near-infrared data have contributed to unveiling massive and obscured stellar populations in both new and previously known clusters in our Galaxy. These discoveries have lead us to view the Milky Way as an active star-forming machine. We look for young massive cluster candidates as over-densities of OB-type stars. The first search, focused on the Galactic direction l=38, resulted in the detection of two objects with a remarkable population of OB-type star candidates. With a modified version of the friends-of-friends algorithm AUTOPOP and using 2MASS and UKIDSS-GPS near-infrared (J, H, and K) photometry for one of our cluster candidates (Masgomas-6) we selected 30 stars for multi-object and long-slit H and K band spectroscopy. With the spectral classification and the near-infrared photometric data, we derive individual distance, extinction, and radial velocity. Of the 30 spectroscopically observed stars, 20 are classified as massive stars, including OB-types (dwarfs, giants and supergiants), two red supergiants, two Wolf-Rayets (WR122-11 and the new WR122-16), and one transitional object (the LBV candidate IRAS 18576+0341). The individual distances and radial velocities do not agree with a single cluster, indicating that we are observing two populations of massive stars in the same line of sight: Masgomas-6a and Masgomas-6b. The first group of massive stars, located at 3.9kpc, contains both Wolf-Rayets and most of the OB-dwarfs; the second group, located at 9.6kpc, hosts the LBV candidate and an evolved population of supergiants. We are able to identify massive stars at two Galactic arms, but we cannot clearly identify whether these massive stars form clusters or associations.
- ID:
- ivo://CDS.VizieR/II/246
- Title:
- 2MASS All-Sky Catalog of Point Sources
- Short Name:
- II/246
- 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 sensitivity of 17.1, 16.4 and 15.3mag in the 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).
- 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).
- 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.
