- ID:
- ivo://CDS.VizieR/J/PASJ/70/28
- Title:
- Subaru HSC counterpart candidates of GW170817
- Short Name:
- J/PASJ/70/28
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We perform a z-band survey for an optical counterpart of the binary neutron star coalescence GW170817 with Subaru/Hyper Suprime-Cam. Our untargeted transient search covers 23.6deg^2^ corresponding to the 56.6% credible region of GW170817 and reaches the 50% completeness magnitude of 20.6mag on average. As a result, we find 60 candidate extragalactic transients, including J-GEM17btc (also known as SSS17a/DLT17ck). While J-GEM17btc is associated with NGC 4993, which is firmly located inside the 3D skymap of GW170817, the other 59 candidates do not have distance information in the GLADE v2 catalog or NASA/IPAC Extragalactic Database. Among 59 of the candidates, 58 are located at the center of extended objects in the Pan-STARRS1 catalog, while one candidate has an offset. We present location, z-band apparent magnitude, and time variability of the candidates and evaluate the probabilities that they are located within the 3D skymap of GW170817. The probability for J-GEM17btc is 64%, which is much higher than for the other 59 candidates (9.3x10^-3^-2.1x10^-1^%). Furthermore, the possibility that at least one of the other 59 candidates is located within the 3D skymap is only 3.2%. Therefore, we conclude that J-GEM17btc is the most likely and distinguished candidate to be the optical counterpart of GW170817.
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Search Results
- ID:
- ivo://CDS.VizieR/J/ApJ/778/L13
- Title:
- Subaru new Ca filter transmission function
- Short Name:
- J/ApJ/778/L13
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recent spectroscopic observations of the outer halo globular cluster (GC) NGC 2419 show that it is unique among GCs, in terms of chemical abundance patterns, and some suggest that it was originated in the nucleus of a dwarf galaxy. Here we show, from the Subaru narrowband photometry employing a calcium filter, that the red giant branch (RGB) of this GC is split into two distinct subpopulations. Comparison with spectroscopy has confirmed that the redder RGB stars in the hk[=(Ca-b)-(b-y)] index are enhanced in [Ca/H] by ~0.2dex compared to the bluer RGB stars. Our population model further indicates that the calcium-rich second generation stars are also enhanced in helium abundance by a large amount ({Delta}Y=0.19). Our photometry, together with the results for other massive GCs (e.g., {omega} Cen, M22, and NGC 1851), suggests that the discrete distribution of RGB stars in the hk index might be a universal characteristic of this growing group of peculiar GCs. The planned narrowband calcium photometry for the Local Group dwarf galaxies would help to establish an empirical connection between these GCs and the primordial building blocks in the hierarchical merging paradigm of galaxy formation.
- ID:
- ivo://CDS.VizieR/J/PASJ/68/92
- Title:
- Subaru NIR obs. of Pleiades stars in SEEDS survey
- Short Name:
- J/PASJ/68/92
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We find a new substellar companion to the Pleiades member star, Pleiades HII 3441, using the Subaru telescope with adaptive optics. The discovery is made as part of the high-contrast imaging survey to search for planetary-mass and substellar companions in the Pleiades and young moving groups. The companion has a projected separation of 0.49+/-0.02 (66+/-2au) and a mass of 68+/-5MJ based on three observations in the J-, H-, and Ks-bands. The spectral type is estimated to be M7 (~2700K), and thus no methane absorption is detected in the H band. Our Pleiades observations result in the detection of two substellar companions including one previously reported among 20 observed Pleiades stars, and indicate that the fraction of substellar companions in the Pleiades is about 10.0^+26.1^_-8.8_%. This is consistent with multiplicity studies of both the Pleiades stars and other open clusters.
- ID:
- ivo://CDS.VizieR/J/ApJ/882/L22
- Title:
- Subaru obs. of Vesta in MIR spectral range
- Short Name:
- J/ApJ/882/L22
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Plagioclase feldspars are among the most prevalent minerals in the solar system, and are present in many chondritic and achondritic meteorite families. Nevertheless, spectral features of plagioclases have never been unambiguously and directly observed in remote observations of asteroids. We report here the detection of an absorption band at 12.2{mu}m on Vesta spectra provided by ground-based spectral observations at the Subaru Telescope. This signature represents the first direct evidence of a widespread presence of crystalline Ca-rich plagioclase on Vesta and reveals that its regolith is comminuted to a very fine grain size, smaller than a few tens of microns, indicating that the mechanical brecciation process has been very effective. The crystalline nature of plagioclase strongly suggests that impacts alone cannot be the sole mechanism for regolith formation on Vesta and a milder process, such as thermal fatigue, should be invoked as an important and concomitant process Thermal fatigue should be considered a very effective process in regolith production and rejuvenation not only for near-Earth asteroids but even for large asteroids located in the main belt.
- ID:
- ivo://CDS.VizieR/J/ApJS/225/11
- Title:
- Subaru-UDGs in the Coma cluster
- Short Name:
- J/ApJS/225/11
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a catalog of ultra-diffuse galaxies (UDGs) in the Coma cluster. UDGs are a subset of low surface brightness (SB) galaxies with very large effective radii defined by van Dokkum et al. (2015ApJ...798L..45V). We surveyed the Subaru data archive for deep Suprime-Cam/Subaru R-band images, and used data covering the 1.7x2.7{deg} region of the Coma cluster. The data are ~1 magnitude deeper than the data of van Dokkum et al. in limiting SB. This paper explains the details of our sample selection procedure. This UDG catalog includes positions, magnitudes, effective radii, mean and central SBs, and colors (when available). Comparisons with previous galaxy catalogs in the literature are performed, and we show that the current catalog is the largest for UDGs. We also discuss that most of the UDGs are members of the Coma cluster, and the major axis of the UDGs tends to align toward the cluster center (radial alignment).
- ID:
- ivo://CDS.VizieR/J/ApJ/669/714
- Title:
- Subaru weak-lensing survey. I.
- Short Name:
- J/ApJ/669/714
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of an ongoing weak-lensing survey conducted with the Subaru Telescope whose initial goal is to locate and study the distribution of shear-selected structures, or halos. Using a Suprime-Cam imaging survey spanning 21.82deg^2^, we present a catalog of 100 candidate halos located from lensing-convergence maps. Our sample is reliably drawn from that subset of our survey area (totaling 16.72deg^2^) uncontaminated by bright stars and edge effects and is limited at a convergence signal-to-noise ratio of 3.69. To validate the sample, detailed spectroscopic measures have been made for 26 candidates using the Subaru multiobject spectrograph, FOCAS. All are confirmed as clusters of galaxies, but two arise as the superposition of multiple clusters viewed along the line of sight. Including data available in the literature and an ongoing Keck spectroscopic campaign, a total of 41 halos now have reliable redshifts.
- ID:
- ivo://CDS.VizieR/J/MNRAS/421/3060
- Title:
- Subaru/XMM Deep Field radio imaging. III.
- Short Name:
- J/MNRAS/421/3060
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present spectroscopic and 11-band photometric redshifts for galaxies in the 100-uJy Subaru/XMM-Newton Deep Field radio source sample. We find good agreement between our redshift distribution and that predicted by the Square Kilometre Array (SKA) Simulated Skies project. We find no correlation between K-band magnitude and radio flux, but show that sources with 1.4-GHz flux densities below ~1mJy are fainter in the near-infrared than brighter radio sources at the same redshift, and we discuss the implications of this result for spectroscopically incomplete samples where the K-z relation has been used to estimate redshifts. We use the infrared-radio correlation to separate our sample into radio-loud and radio-quiet objects and show that only radio-loud hosts have spectral energy distributions consistent with predominantly old stellar populations, although the fraction of objects displaying such properties is a decreasing function of radio luminosity.
- ID:
- ivo://CDS.VizieR/J/ApJS/176/301
- Title:
- Subaru/XMM-Newton deep survey IV. (SXDS)
- Short Name:
- J/ApJS/176/301
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present luminosity functions (LFs) and various properties of Ly{alpha} emitters (LAEs) at z=3.1, 3.7, and 5.7, in a 1deg^2^ sky of the Subaru/XMM-Newton Deep Survey (SXDS) Field. We obtain a photometric sample of 858 LAE candidates based on deep Subaru Suprime-Cam imaging data and a spectroscopic sample of 84 confirmed LAEs from Subaru FOCAS and VLT VIMOS spectroscopy in a survey volume of ~10^6^Mpc^3^ with a limiting Ly{alpha} luminosity of ~3x10^42^ergs/s. We derive the LFs of the Ly{alpha} and UV continuum (~1500{AA}) for each redshift, taking into account the statistical error and the field-to-field variation. We identify six LAEs with AGN activities from our spectra combined with VLA, Spitzer, and XMM-Newton data. Among the photometrically selected LAEs at z=3.1 and 3.7, only ~1% show AGN activities, while the brightest LAEs with logL(Ly{alpha})>~43.4-43.6ergs/s appear to always host AGNs. Our LAEs are bluer in UV-continuum color than dropout galaxies, suggesting lower extinction and/or younger stellar populations.
- ID:
- ivo://CDS.VizieR/J/ApJS/176/1
- Title:
- Subaru/XMM-Newton deep survey (SXDS). II.
- Short Name:
- J/ApJS/176/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present multi-wave band optical imaging data obtained from observations of the Subaru/XMM-Newton Deep Survey (SXDS). The survey field, centered at RA=02:18:00, DE=-05:00:00, has been the focus of a wide range of multiwavelength observing programs spanning from X-ray to radio wavelengths. A large part of the optical imaging observations are carried out with Suprime-Cam on Subaru Telescope at Mauna Kea in the course of Subaru Telescope "Observatory Projects".
- ID:
- ivo://CDS.VizieR/J/ApJS/179/124
- Title:
- Subaru/XMM-Newton deep survey (SXDS) III.
- Short Name:
- J/ApJS/179/124
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the X-ray source catalog in the Subaru/XMM-Newton deep survey. A continuous area of 1.14deg^2^ centered at RA=02h18m and DE=-05{deg} is mapped by seven pointings with XMM-Newton covering the 0.2-10keV band. From the combined images of the EPIC pn and MOS cameras, we detect 866, 1114, 645, and 136 sources with sensitivity limits of 6x10^-16^, 8x10^-16^, 3x10^-15^, and 5x10^-15^ergs/cm^2^/s in the 0.5-2, 0.5-4.5, 2-10, and 4.5-10keV bands, respectively, with detection likelihood >=7 (corresponding to a confidence level of 99.91%). The catalog consists of 1245 sources in total including 32 extended-source candidates. The averaged logN-logS relations are in good agreement with previous results, bridging the flux range between Chandra deep surveys and brighter surveys.