- ID:
- ivo://CDS.VizieR/J/MNRAS/469/4578
- Title:
- Deep learning classification in asteroseismology
- Short Name:
- J/MNRAS/469/4578
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In the power spectra of oscillating red giants, there are visually distinct features defining stars ascending the red giant branch from those that have commenced helium core burning. We train a 1D convolutional neural network by supervised learning to automatically learn these visual features from images of folded oscillation spectra. By training and testing on Kepler red giants, we achieve an accuracy of up to 99 per cent in separating helium-burning red giants from those ascending the red giant branch. The convolutional neural network additionally shows capability in accurately predicting the evolutionary states of 5379 previously unclassified Kepler red giants, by which we now have greatly increased the number of classified stars.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/863/25
- Title:
- Deep Magellan/Megacam obs. of 4 MW satellites
- Short Name:
- J/ApJ/863/25
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present deep Magellan/Megacam stellar photometry of four recently discovered faint Milky Way satellites: Sagittarius II (Sgr II), Reticulum II (Ret II), Phoenix II (Phe II), and Tucana III (Tuc III). Our photometry reaches ~2-3 magnitudes deeper than the discovery data, allowing us to revisit the properties of these new objects (e.g., distance, structural properties, luminosity measurements, and signs of tidal disturbance). The satellite color-magnitude diagrams show that they are all old (~13.5Gyr) and metal poor ([Fe/H]<~-2.2). Sgr II is particularly interesting, as it sits in an intermediate position between the loci of dwarf galaxies and globular clusters in the size-luminosity plane. The ensemble of its structural parameters is more consistent with a globular cluster classification, indicating that Sgr II is the most extended globular cluster in its luminosity range. The other three satellites land directly on the locus defined by Milky Way ultra-faint dwarf galaxies of similar luminosity. Ret II is the most elongated nearby dwarf galaxy currently known for its luminosity range. Our structural parameters for Phe II and Tuc III suggest that they are both dwarf galaxies. Tuc III is known to be associated with a stellar stream, which is clearly visible in our matched-filter stellar density map. The other satellites do not show any clear evidence of tidal stripping in the form of extensions or distortions. Finally, we also use archival HI data to place limits on the gas content of each object.
- ID:
- ivo://CDS.VizieR/J/MNRAS/391/1384
- Title:
- Deep MERLIN 5GHz radio sources in M82
- Short Name:
- J/MNRAS/391/1384
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of an extremely deep, 8-d long observation of the central kpc of the nearby starburst galaxy M82 using Multi-Element Radio Linked Interferometer Network (MERLIN) at 5GHz are presented. The 17{mu}Jy/beam rms noise level in the naturally weighted image makes it the most sensitive high-resolution radio image of M82 made to date. Over 50 discrete sources are detected, the majority of which are supernova remnants, but with 13 identified as H ii regions. Sizes, flux densities and radio brightnesses are given for all of the detected sources, which are all well resolved with a majority showing shell or partial shell structures. Those sources within the sample which are supernova remnants have diameters ranging from 0.3 to 6.7pc, with a mean size of 2.9pc.
- ID:
- ivo://CDS.VizieR/J/MNRAS/383/75
- Title:
- Deep 610MHz survey of ELAIS-N1 sources
- Short Name:
- J/MNRAS/383/75
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Observations of the ELAIS-N1 field taken at 610MHz with the Giant Metrewave Radio Telescope are presented. Nineteen pointings were observed, covering a total area of 9 square degrees with a resolution of 6x5arcsec^2^, PA=45deg. Four of the pointings were deep observations with an rms of ~40uJy before primary beam correction, with the remaining fifteen pointings having an rms of ~70uJy. The techniques used for data reduction and production of a mosaicked image of the region are described, and the final mosaic, along with a catalogue of 2500 sources detected above 6{sigma}, are presented. This work complements the large amount of optical and infrared data already available on the region. For further details of the surveys and data analysis procedures please refer to the published paper.
- ID:
- ivo://CDS.VizieR/J/AJ/138/703
- Title:
- Deep MIPS observations of IC 348 nebula
- Short Name:
- J/AJ/138/703
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We describe new, deep MIPS photometry and new high signal-to-noise optical spectroscopy of the 2.5Myr old IC 348 Nebula. To probe the properties of the IC 348 disk population, we combine these data with previous optical/infrared photometry and spectroscopy to identify stars with gas accretion, to examine their mid-IR colors, and to model their spectral energy distributions.
- ID:
- ivo://CDS.VizieR/J/ApJS/119/189
- Title:
- Deep Multicolor Survey. IV.
- Short Name:
- J/ApJS/119/189
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This stellar catalog contains 19,494 objects from the Deep Multicolor Survey (DMS) and results from follow-up spectroscopic observations of 234 objects in the catalog. The DMS is based on CCD imaging with the Mayall 4 m telescope in U, B, V, R', I75, and I86 and covers 0.83 deg^2 in six fields at high Galactic latitude. The survey reached 5 sigma limiting magnitudes of 22.1 in I86 to 23.8 in B. The catalog gives positions, magnitudes and error estimates, and classification codes in the six filter bands for all the objects. In addition, the survey is useful for the study of faint field galaxies and of faint stars at high Galactic latitude. Presented are tables that summarize the spectroscopic results for the 55 quasars, 44 compact narrow emission-line galaxies, and 135 stars in the DMS that we have confirmed to date. Also included are illustrations of all the spectra.
- ID:
- ivo://wfau.roe.ac.uk/denis-dsa
- Title:
- Deep Near Infrared Survey of the Southern Sky (DENIS)
- Date:
- 04 Dec 2019 13:34:37
- Publisher:
- WFAU, Institute for Astronomy, University of Edinburgh
- Description:
- Catalog of astrometry and photometry of detected point sources in the Far red optical (0.82-micron I-band) and near-infrared (1.25-micron J- and 2.15-micron Ks bands). ~16,700 square degrees of the southern sky
- ID:
- ivo://irsa.ipac/DENIS/Catalog
- Title:
- Deep Near-Infrared Survey of the Southern Sky (DENIS) Catalog
- Short Name:
- DENIS
- Date:
- 04 Dec 2017 21:44:08
- Publisher:
- NASA/IPAC Infrared Science Archive
- Description:
- This data release, from 2005 September, consists of 355,220,325 point sources detected by DENIS. The release contains 3662 strips, each of which is 30 degrees long in Declination and 12 arcmin wide in Right Ascension (with an overlap of 2 arcminutes between consecutive strips), and covers approximately 16,700 square degrees of the southern sky. The northernmost declination covered is ~+02d07m and the southernmost is ~-87d37m. Multiple detections of single point sources have been merged in image overlaps within individual strips, but sources can have multiple detections in overlapping strips. DENIS observations began at the end of 1995 and were completed on 09 September 2001. The survey was conducted simultaneously in three bands: one optical band (Gunn-i at 0.82um, hereafter referred to as "I") and two near-infrared bands (J at 1.25um and Ks at 2.15um), with limiting magnitudes of 18.5 mag, 16.5 mag, and 14.0 mag and saturation magnitudes of 9.8 mag, 7.5 mag, and 6 mag at I, J, and Ks, respectively. Documentation at CDS states that the astrometric accuracy of a typical point source is better than 1 arcsec and photometric accuracy is better than 0.1 mag, although the range of SNR over which these apply is not specified. DENIS was conducted by a European consortium using the 1m telescope at the European Southern Observatory in La Silla, Chile.
- ID:
- ivo://CDS.VizieR/J/MNRAS/462/3386
- Title:
- Deep NIR catalogue of HIZOA galaxies
- Short Name:
- J/MNRAS/462/3386
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a deep near-infrared (NIR; J, H, and K_s_ bands) photometric catalogue of sources from the Parkes HI Zone of Avoidance (HIZOA) survey, which forms the basis for an investigation of the matter distribution in the Zone of Avoidance. Observations were conducted between 2006 and 2013 using the Infrared Survey Facility (IRSF), a 1.4-m telescope situated at the South African Astronomical Observatory site in Sutherland. The images cover all 1108 HIZOA detections and yield 915 galaxies. An additional 105 bright 2MASS galaxies in the southern ZOA were imaged with the IRSF, resulting in 129 galaxies. The average K_s_-band seeing and sky background for the survey are 1.38-arcsec and 20.1mag, respectively. The detection rate as a function of stellar density and dust extinction is found to depend mainly on the HI mass of the HI detected galaxies, which in principal correlates with the NIR brightness of the spiral galaxies. The measured isophotal magnitudes are of sufficient accuracy (errors ~0.02mag) to be used in a Tully-Fisher analysis. In the final NIR catalogue, 285 galaxies have both IRSF and 2MASS photometry (180 HIZOA plus 105 bright 2MASX galaxies). The K_s_-band isophotal magnitudes presented in this paper agree, within the uncertainties, with those reported in the 2MASX catalogue. Another 30 galaxies, from the HIZOA northern extension, are also covered by UKIDSS Galactic Plane Survey (GPS) images, which are one magnitude deeper than our IRSF images. A modified version of our photometry pipeline was used to derive the photometric parameters of these UKIDSS galaxies. Good agreement was found between the respective K_s_-band isophotal magnitudes. These comparisons confirm the robustness of the isophotal parameters and demonstrate that the IRSF images do not suffer from foreground contamination, after star removal, nor underestimate the isophotal fluxes of ZoA galaxies.
- ID:
- ivo://CDS.VizieR/J/ApJ/719/550
- Title:
- Deep NIR imaging of {rho} Oph cloud core
- Short Name:
- J/ApJ/719/550
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A search for young substellar objects in the {rho} Oph cloud core region has been made with the aid of multiband profile-fitting point-source photometry of the deep-integration Combined Calibration Scan images of the 2MASS extended mission in the J, H, and Ks bands, and Spitzer IRAC images at 3.6, 4.5, 5.8, and 8.0um. The field of view of the combined observations was 1{deg}x9.3', and the 5{sigma} limiting magnitude at J was 20.5. Comparison of the observed spectral energy distributions with the predictions of the COND and DUSTY models, for an assumed age of 1Myr, supports the identification of many of the sources with brown dwarfs and enables the estimation of effective temperature, T_eff_. The cluster members are then readily distinguishable from background stars by their locations on a plot of flux density versus T_eff_. The range of estimated T_eff_ values extends down to ~750K which, based on the COND model, would suggest the presence of objects of sub-Jupiter mass. The results also suggest that the mass function for the {rho} Oph cloud resembles that of the {sigma} Orionis cluster based on a recent study, with both rising steadily toward lower masses. The other main result from our study is the apparent presence of a progressive blueward skew in the distribution of J-H and H-Ks colors, such that the blue end of the range becomes increasingly bluer with increasing magnitude. We suggest that this behavior might be understood in terms of the "ejected stellar embryo" hypothesis, whereby some of the lowest-mass brown dwarfs could escape to locations close to the front edge of the cloud, and thereby be seen with less extinction.