- ID:
- ivo://CDS.VizieR/J/ApJ/868/47
- Title:
- The 1st year of the Swift SMC Survey (S-CUBED)
- Short Name:
- J/ApJ/868/47
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Swift Small Magellanic Cloud (SMC) Survey, S-CUBED, is a high-cadence shallow X-ray survey of the SMC. The survey consists of 142 tiled pointings covering the optical extent of the SMC, which is performed weekly by NASA's Neil Gehrels Swift Observatory, with an exposure per tile of 60s. The survey is focused on discovery and monitoring of X-ray outbursts from the large known and unknown population of Be/X-ray binaries (BeXRBs) in the SMC. Given the very low background of Swift's X-ray telescope, even with a short exposure per tile, S-CUBED is typically sensitive to outbursts in the SMC at >1%-2% Eddington luminosity for a typical 1.4M_{sun}_ neutron star compact object. This sensitivity, combined with the high cadence and the fact that the survey can be performed all year round, makes it a powerful discovery tool for outbursting accreting X-ray pulsars in the SMC. In this paper we describe results from the first year of observations of S-CUBED, which includes the 1SCUBEDX catalog of 265 X-ray sources, 160 of which are not identified with any previously cataloged X-ray source. We report on bulk properties of sources in the 1SCUBEDX catalog. Finally, we focus on results of S-CUBED observations of several interesting sources, which includes discovery of three Type II outbursts from BeXRBs and the detection of Type I outbursts and orbital periods in six BeXRB systems.
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- ID:
- ivo://CDS.VizieR/J/ApJ/723/845
- Title:
- The submillimeter spectrum of glycolaldehyde
- Short Name:
- J/ApJ/723/845
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Glycolaldehyde (HOCH_2_CHO) is a sugar-related interstellar prebiotic molecule that has been detected in two star-forming regions, Sgr B2(N) and G31.41+0.31. Glycolaldehyde is suspected to form from photodissociation-driven ice chemistry, and therefore can be used to trace complex organic chemistry in interstellar environments. The relative abundance of glycolaldehyde to its structural isomers, methyl formate (HCOOCH_3_) and acetic acid (CH_3_COOH), can be used to constrain astrochemical models. Given its central role in the complex chemistry of the interstellar medium, glycolaldehyde has been suggested as a prime molecular target for upcoming high-frequency molecular line searches using new far-infrared observatories. In particular, glycolaldehyde is a target for the Herschel Space Observatory HEXOS Key Program, which is conducting spectral line surveys of the Sgr B2(N) and Orion KL star-forming regions across the entire HIFI band. Laboratory investigation of glycolaldehyde in the HIFI frequency range is required before its lines can be identified in these spectra. We have therefore acquired the laboratory spectrum of glycolaldehyde in selected frequency ranges across the submillimeter range. We present here the laboratory spectral analysis of the ground vibrational state of glycolaldehyde up to 1.2THz.
- ID:
- ivo://CDS.VizieR/J/A+A/636/A46
- Title:
- The SUGAR model. Training dataset
- Short Name:
- J/A+A/636/A46
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This analysis develops a new SNe Ia spectral energy distribution (SED) model, called the SUpernova Generator And Reconstructor (SUGAR), which improves the spectral description of SNe Ia, and consequently could improve the distance measurements. This model was constructed from SNe Ia spectral properties and spectrophotometric data from the Nearby Supernova Factory collaboration. In a first step, a principal component analysis-like method was used on spectral features measured at maximum light, which allowed us to extract the intrinsic properties of SNe Ia. Next, the intrinsic properties were used to extract the average extinction curve. Third, an interpolation using Gaussian processes facilitated using data taken at different epochs during the lifetime of an SN Ia and then projecting the data on a fixed time grid. Finally, the three steps were combined to build the SED model as a function of time and wavelength. This is the SUGAR model. The proper way to cite the data can be found at https://snfactory.lbl.gov/snf/data/index.html
- ID:
- ivo://CDS.VizieR/J/MNRAS/462/917
- Title:
- The Super-CLASS GMRT catalogue - SCG
- Short Name:
- J/MNRAS/462/917
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of 325MHz Giant Metrewave Radio Telescope observations of a supercluster field, known to contain five Abell clusters at redshift z~0.2. We achieve a nominal sensitivity of 34uJy/beam towards the phase centre. We compile a catalogue of 3257 sources with flux densities in the range 183uJy-1.5Jy within the entire ~6.5deg^2^ field of view. Subsequently, we use available survey data at other frequencies to derive the spectral index distribution for a sub-sample of these sources, recovering two distinct populations - a dominant population which exhibit spectral index trends typical of steep-spectrum synchrotron emission, and a smaller population of sources with typically flat or rising spectra. We identify a number of sources with ultrasteep spectra or rising spectra for further analysis, finding two candidate high-redshift radio galaxies and three gigahertz-peaked-spectrum radio sources. Finally, we derive the Euclidean-normalized differential source counts using the catalogue compiled in this work, for sources with flux densities in excess of 223uJy. Our differential source counts are consistent with both previous observations at this frequency and models of the low-frequency source population. These represent the deepest source counts yet derived at 325MHz. Our source counts exhibit the well-known flattening at mJy flux densities, consistent with an emerging population of star-forming galaxies; we also find marginal evidence of a downturn at flux densities below 308uJy, a feature so far only seen at 1.4GHz.
- ID:
- ivo://CDS.VizieR/J/A+AS/123/119
- Title:
- The supercluster-void network. I.
- Short Name:
- J/A+AS/123/119
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We use a compilation of redshifts of rich clusters by Andernach, Tago and Stengler-Larrea (1996, in preparation) to determine superclusters of rich clusters up to a redshift of z=0.12. Superclusters were searched for with a clustering algorithm, using a neighbourhood radius of 24h^-1^Mpc (h is the Hubble constant in units of 100km/s/Mpc). The catalogue contains 220 superclusters of rich clusters, of which 90 superclusters have been determined for the first time. Table A2 gives the supercluster number, its multiplicity, centre coordinates, a list of member clusters and identifications with the catalogue by Einasto et al. (1994MNRAS.269..301E).
- ID:
- ivo://CDS.VizieR/J/ApJ/859/101
- Title:
- The supernovae Ia Pantheon sample
- Short Name:
- J/ApJ/859/101
- Date:
- 20 Jan 2022 07:41:10
- Publisher:
- CDS
- Description:
- We present optical light curves, redshifts, and classifications for 365 spectroscopically confirmed Type Ia supernovae (SNe Ia) discovered by the Pan-STARRS1 (PS1) Medium Deep Survey. We detail improvements to the PS1 SN photometry, astrometry, and calibration that reduce the systematic uncertainties in the PS1 SN Ia distances. We combine the subset of 279 PS1 SNe Ia (0.03<z<0.68) with useful distance estimates of SNe Ia from the Sloan Digital Sky Survey (SDSS), SNLS, and various low-z and Hubble Space Telescope samples to form the largest combined sample of SNe Ia, consisting of a total of 1048 SNe Ia in the range of 0.01<z<2.3, which we call the "Pantheon Sample". When combining Planck 2015 cosmic microwave background (CMB) measurements with the Pantheon SN sample, we find {Omega}_m_=0.307+/-0.012 and w=-1.026+/-0.041 for the wCDM model. When the SN and CMB constraints are combined with constraints from BAO and local H_0_ measurements, the analysis yields the most precise measurement of dark energy to date: w_0_=-1.007+/-0.089 and w_a_=-0.222+/-0.407 for the w_0_w_a_CDM model. Tension with a cosmological constant previously seen in an analysis of PS1 and low-z SNe has diminished after an increase of 2x in the statistics of the PS1 sample, improved calibration and photometry, and stricter light-curve quality cuts. We find that the systematic uncertainties in our measurements of dark energy are almost as large as the statistical uncertainties, primarily due to limitations of modeling the low-redshift sample. This must be addressed for future progress in using SNe Ia to measure dark energy.
- ID:
- ivo://CDS.VizieR/J/AJ/113/634
- Title:
- The survival of Sagittarius dwarf galaxy
- Short Name:
- J/AJ/113/634
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Sagittarius dwarf spheroidal galaxy, the closest satellite galaxy of the Milky Way, has survived for many orbits about the Galaxy. Extent numerical calculations modeled this galaxy as a system with a centrally-concentrated mass profile, following the light, and found that it should lose more than one-half of its mass every 2-4 orbits and be completely disrupted long before now. Apparently the Sagittarius dwarf spheroidal, and by implication other dSph galaxies, do not have a centrally-concentrated profile for their dark matter. We develop a model in which the stars of the Sgr dwarf are embedded in a constant-density dark matter halo, representing the core of a tidally-limited system, and show that this is consistent with its survival. We present new photometric and kinematic observations of the Sagittarius dwarf spheroidal and show these data are consistent with this explanation for the continued existence of this galaxy. The Sagittarius dwarf is being tidally distorted and is tidally limited, but is not disrupted as yet. The corresponding minimum total mass is 10^9^M_{sun}_, while the central mass to visual light ratio is ~50 in Solar units. Our new photographic photometry allows the detection of main-sequence stars of the Sagittarius dwarf over an area of 22x8{deg}. The Sagittarius dwarf is prolate, with axis ratios ~3:1:1. For an adopted distance of 16+/-2kpc from the Galactic center on the opposite side of the Galaxy to the Sun, the major axis is >~9kpc long and is aligned approximately normal to the plane of the Milky Way Galaxy, roughly following the coordinate line l=5{deg}. The central velocity dispersion of giant stars which are members of the Sagittarius dwarf is 11.4+/-0.7km/s and is consistent with being constant over the face of the galaxy. The gradient in mean line-of-sight velocity with position along the major axis, dv/db, is ~0km/s/degree in the central regions and increases in amplitude to dv/db=-3km/s/degree over the outermost three degrees for which we have data. A first measurement of the proper motion of the Sagittarius dwarf determines the component of its space velocity parallel to its major axis to be 250+/-90km/s, directed towards the Galactic Plane. We model these kinematic data to determine the orbit of the Sagittarius dwarf. Our best fit model has an orbital period of <~1Gyr and has the Sagittarius dwarf spheroidal close to perigalacticon. This period is shorter, by about a factor of >~10, than the age of the bulk of its stellar population. (Copyright) 1997 American Astronomical Society.
- ID:
- ivo://CDS.VizieR/J/AJ/161/170
- Title:
- The Swan: an approach to derive surface gravity
- Short Name:
- J/AJ/161/170
- Date:
- 20 Jan 2022
- Publisher:
- CDS
- Description:
- Stellar light curves are well known to encode physical stellar properties. Precise, automated, and computationally inexpensive methods to derive physical parameters from light curves are needed to cope with the large influx of these data from space-based missions such as Kepler and TESS. Here we present a new methodology that we call "The Swan", a fast, generalizable, and effective approach for deriving stellar surface gravity (logg) for main-sequence, subgiant, and red giant stars from Kepler light curves using local linear regression on the full frequency content of Kepler long-cadence power spectra. With this inexpensive data-driven approach, we recover logg to a precision of ~0.02dex for 13822 stars with seismic logg values between 0.2 and 4.4dex and ~0.11dex for 4646 stars with Gaia-derived logg values between 2.3 and 4.6dex. We further develop a signal-to-noise metric and find that granulation is difficult to detect in many cool main-sequence stars (Teff<~5500K), in particular K dwarfs. By combining our logg measurements with Gaia radii, we derive empirical masses for 4646 subgiant and main-sequence stars with a median precision of ~7%. Finally, we demonstrate that our method can be used to recover logg to a similar mean absolute deviation precision for a TESS baseline of 27days. Our methodology can be readily applied to photometric time series observations to infer stellar surface gravities to high precision across evolutionary states.
- ID:
- ivo://CDS.VizieR/J/ApJS/209/14
- Title:
- The Swift/BAT hard X-ray transient monitor
- Short Name:
- J/ApJS/209/14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Swift/Burst Alert Telescope (BAT) hard X-ray transient monitor provides near real-time coverage of the X-ray sky in the energy range 15-50 keV. The BAT observes 88% of the sky each day with a detection sensitivity of 5.3 mCrab for a full-day observation and a time resolution as fine as 64s. The three main purposes of the monitor are (1) the discovery of new transient X-ray sources, (2) the detection of outbursts or other changes in the flux of known X-ray sources, and (3) the generation of light curves of more than 900 sources spanning over eight years. The primary interface for the BAT transient monitor is a public Web site. Between 2005 February 12 and 2013 April 30, 245 sources have been detected in the monitor, 146 of them persistent and 99 detected only in outburst. Among these sources, 17 were previously unknown and were discovered in the transient monitor. In this paper, we discuss the methodology and the data processing and filtering for the BAT transient monitor and review its sensitivity and exposure. We provide a summary of the source detections and classify them according to the variability of their light curves. Finally, we review all new BAT monitor discoveries. For the new sources that are previously unpublished, we present basic data analysis and interpretations.
- ID:
- ivo://CDS.VizieR/J/AN/341/989
- Title:
- theta Cep radial velocity curve
- Short Name:
- J/AN/341/989
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In 2015 a radial velocity monitoring campaign was started in order to redetermine and/or constrain the orbital solutions of spectroscopic binary systems. The observations were carried out at the University Observatory Jena with the echelle spectrograph FLECHAS. The results from the main part of our target sample are already published. For the final target of this campaign, theta Cep, we can now present an orbital solution based on a homogeneously covered radial velocity curve. The period of this single-lined spectroscopic binary turns out to be significantly larger and the orbit is much more eccentric compared to the given values in the 9th Catalogue of Spectroscopic Binary Orbits (Pourbaix et al., Cat. B/sb9).