- 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).
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/132/781
- Title:
- 2MASS colours of Magellanic cloud star clusters
- Short Name:
- J/AJ/132/781
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The (rest-frame) near-IR domain contains important stellar population diagnostics and is often used to estimate masses of galaxies at low, as well as high, redshifts. However, many stellar population models are still relatively poorly calibrated in this part of the spectrum. To allow an improvement of this calibration we present a new database of integrated nearIR JHKs magnitudes for 75 star clusters in the Magellanic Clouds, using the Two Micron All Sky Survey (2MASS). The majority of the clusters in our sample have robust age and metallicity estimates from color-magnitude diagrams available in the literature, and populate a range of ages from 10Myr to 15Gyr and a range in [Fe/H] from -2.17 to +0.01dex. A comparison with matched star clusters in the 2MASS Extended Source Catalog (XSC) reveals that the XSC only provides a good fit to the unresolved component of the cluster stellar population. We also compare our results with the often-cited single-channel JHK photometry of Persson and coworkers (1983ApJ...266..105P).
- 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/ApJ/686/L115
- Title:
- Masses of evolved disks in PMS stars
- Short Name:
- J/ApJ/686/L115
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report deep Submillimeter Array observations of 26 pre-main-sequence (PMS) stars with evolved inner disks. These observations measure the mass of the outer disk (r~20-100AU) across every stage of the dissipation of the inner disk (r<10AU) as determined by the IR spectral energy distributions (SEDs). We find that only targets with high mid-IR excesses are detected and have disk masses in the 1-5M_Jup_ range, while most of our objects remain undetected to sensitivity levels of M_DISK_~0.2-1.5M_Jup_. To put these results in a more general context, we collected publicly available data to construct the optical to millimeter wavelength SEDs of over 120 additional PMS stars. We find that the near-IR and mid-IR emissions remain optically thick in objects whose disk masses span 2 orders of magnitude (~0.5-50M_Jup_). Taken together, these results imply that, in general, inner disks start to dissipate only after the outer disk has been significantly depleted of mass. This provides strong support for photoevaporation being one of the dominant processes driving disk evolution.
- ID:
- ivo://CDS.VizieR/J/MNRAS/434/3236
- Title:
- Masses of Praesepe members
- Short Name:
- J/MNRAS/434/3236
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have determined possible cluster members of the nearby open cluster Praesepe (M44) based on J and K photometry and proper motions from the PPMXL catalogue and z photometry from the Sloan Digital Sky Survey. In total, we identified 893 possible cluster members down to a magnitude of J=15.5mag, corresponding to a mass of about 0.15M_{sun}_ for an assumed cluster distance modulus of (m-M)0=6.30mag (d~182pc), within a radius of 3.5{deg} around the cluster centre. We derive a new cluster centre for Praesepe (RA_centre_=8:39:37, DE_centre_=19:35:02). We also derive a total cluster mass of about 630M_{sun}_, and a 2D half-number and half-mass radius of 4.25 and 3.90pc, respectively.
- ID:
- ivo://CDS.VizieR/J/A+A/540/A57
- Title:
- Mass function of Quintuplet cluster
- Short Name:
- J/A+A/540/A57
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The stellar mass function is a probe for a potential dependence of star formation on the environment. Only a few young clusters are known to reside within the central molecular zone and can serve as test-beds for star formation under the extreme conditions in this region. We determine the present-day mass function of the Quintuplet cluster, a young massive cluster in the vicinity of the Galactic centre. We use two epochs of high resolution near infrared imaging data obtained with NAOS/CONICA at the ESO VLT to measure the individual proper motions of stars in the Quintuplet cluster in the cluster reference frame. An unbiased sample of cluster members within a radius of 0.5pc from the cluster centre was established based on their common motion with respect to the field and a subsequent colour-cut. Initial stellar masses were inferred from four isochrones covering ages from 3 to 5Myr and two sets of stellar evolution models. For each isochrone, the present-day mass function of stars was determined for the full sample of main sequence cluster members using an equal number binning scheme. We find the slope of the present-day mass function in the central part of the Quintuplet cluster to be alpha=-1.68^+0.13^_-0.09_ for an approximate mass range from 5 to 40M_{sun}_, which is significantly flatter than the Salpeter slope of alpha=-2.35. The flattening of the present-day mass function may be caused by rapid dynamical evolution of the cluster in the strong Galactic centre tidal field. The derived mass function slope is compared to the values found in other young massive clusters in the Galaxy.
- ID:
- ivo://CDS.VizieR/J/AJ/149/171
- Title:
- 2MASS galaxy group catalog
- Short Name:
- J/AJ/149/171
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A galaxy group catalog is built from the sample of the 2MASS Redshift Survey almost complete to K_s_=11.75 over 91% of the sky. Constraints in the construction of the groups were provided by scaling relations determined by close examination of well defined groups with masses between 10^11^ and 10^15^M_{sun}_. Group masses inferred from K_s_ luminosities are statistically in agreement with masses calculated from application of the virial theorem. While groups have been identified over the full redshift range of the sample, the properties of the nearest and farthest groups are uncertain and subsequent analysis has only considered groups with velocities between 3000 and 10000km/s. The 24044 galaxies in this range are identified with 13607 entities, 3461 of them with two or more members. A group mass function is constructed. The Sheth-Tormen formalism provides a good fit to the shape of the mass function for group masses above 6h^-1^x10^12^M_{sun}_ but the count normalization is poor. Summing all the mass associated with the galaxy groups between 3000 and 10000km/s gives a density of collapsed matter as a fraction of the critical density of {Omega}_collapsed_=0.16.
- ID:
- ivo://CDS.VizieR/J/ApJS/203/33
- Title:
- 2MASS interferometric calibrator candidates
- Short Name:
- J/ApJS/203/33
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We aim to provide a list of sources found to be unresolved from direct observations with high angular resolution and dynamic range, which can be used to choose interferometric calibrators. To this purpose, we have used a large number of lunar occultations recorded with the ISAAC instrument at the Very Large Telescope to select sources found to be unresolved and without close companions. An algorithm has been used to determine the limiting angular resolution achieved for each source, taking into account a noise model built from occulted and unocculted portions of the light curves. We have obtained upper limits on the angular sizes of 556 sources, with magnitudes ranging from Ks~4 to 10, with a median of 7.2mag. The upper limits on possible undetected companions (within ~0.5") range from Ks~8 to 13, with a median of 11.5mag. One-third of the sources have angular sizes <=1mas, and two-thirds have sizes <=2mas. This list of unresolved sources matches well the capabilities of current large interferometric facilities. We also provide available cross-identifications, magnitudes, spectral types, and other auxiliary information. A fraction of the sources are found to be potentially variable. The list covers parts of the Galactic Bulge and in particular the vicinity of the Galactic Center, where extinction is very significant and traditional lists of calibrators are often insufficient.
- ID:
- ivo://CDS.VizieR/J/ApJ/834/122
- Title:
- Massive star formation in the LMC. I. N159 & N160
- Short Name:
- J/ApJ/834/122
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present images and spectral energy distributions (SEDs) of massive young stellar objects (YSOs) in three star-forming H II regions of the Large Magellanic Cloud: N159A, N159 Papillon, and N160. We use photometry from SOFIA/FORCAST at 25.3-37.1{mu}m to constrain model fits to the SEDs and determine luminosities, ages, and dust content of the embedded YSOs and their local environments. By placing these sources on mid-infrared color-magnitude and color-color diagrams, we analyze their dust properties and consider their evolutionary status. Since each object in the FORCAST images has an obvious bright near-infrared counterpart in Spitzer Space Telescope images, we do not find any evidence for new, very cool, previously undiscovered Class 0 YSOs. Additionally, based on its mid-infrared colors and model parameters, N159A is younger than N160 and the Papillon. The nature of the first extragalactic protostars in N159, P1, and P2, is also discussed.
- ID:
- ivo://CDS.VizieR/J/ApJ/864/136
- Title:
- Massive star-forming regions multiwavelength study
- Short Name:
- J/ApJ/864/136
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a multiwavelength study of 28 Galactic massive star-forming HII regions. For 17 of these regions, we present new distance measurements based on Gaia DR2 parallaxes. By fitting a multicomponent dust, blackbody, and power-law continuum model to the 3.6{mu}m through 10mm spectral energy distributions, we find that ~34% of Lyman continuum photons emitted by massive stars are absorbed by dust before contributing to the ionization of HII regions, while ~68% of the stellar bolometric luminosity is absorbed and reprocessed by dust in the HII regions and surrounding photodissociation regions. The most luminous, infrared-bright regions that fully sample the upper stellar initial mass function (ionizing photon rates N_C_>=10^50^s^-1^ and dust-processed L_TIR_>=10^6.8^L_{sun}_) have on average higher percentages of absorbed Lyman continuum photons (~51%) and reprocessed starlight (~82%) compared to less luminous regions. Luminous HII regions show lower average polycyclic aromatic hydrocarbon (PAH) fractions than less luminous regions, implying that the strong radiation fields from early-type massive stars are efficient at destroying PAH molecules. On average, the monochromatic luminosities at 8, 24, and 70{mu}m combined carry 94% of the dust-reprocessed L_TIR_. L70 captures ~52% of L_TIR_, and is therefore the preferred choice to infer the bolometric luminosity of dusty star-forming regions. We calibrate star formation rates (SFRs) based on L24 and L70 against the Lyman continuum photon rates of the massive stars in each region. Standard extragalactic calibrations of monochromatic SFRs based on population synthesis models are generally consistent with our values.
