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2941. Properties of yellow supergiant stars in the SMC
ID:
ivo://CDS.VizieR/J/AJ/155/207
Title:
Properties of yellow supergiant stars in the SMC
Short Name:
J/AJ/155/207
Date:
21 Oct 2021
Publisher:
CDS
Description:
We recently discovered a yellow supergiant (YSG) in the Small Magellanic Cloud (SMC) with a heliocentric radial velocity of ~300 km/s, which is much larger than expected for a star at its location in the SMC. This is the first runaway YSG ever discovered and only the second evolved runaway star discovered in a galaxy other than the Milky Way. We classify the star as G5-8 I and use de-reddened broad-band colors with model atmospheres to determine an effective temperature of 4700+/-250 K, consistent with what is expected from its spectral type. The star's luminosity is then log L/L_{sun}_~4.2~0.1, consistent with it being a ~30 Myr 9 M_{sun}_ star according to the Geneva evolution models. The star is currently located in the outer portion of the SMC's body, but if the star's transverse peculiar velocity is similar to its peculiar radial velocity, in 10 Myr the star would have moved 1.6{deg} across the disk of the SMC and could easily have been born in one of the SMC's star-forming regions. Based on its large radial velocity, we suggest it originated in a binary system where the primary exploded as a supernovae, thus flinging the runaway star out into space. Such stars may provide an important mechanism for the dispersal of heavier elements in galaxies given the large percentage of massive stars that are runaways. In the future, we hope to look into additional evolved runaway stars that were discovered as part of our other past surveys.
2942. PSCz catalog
ID:
ivo://CDS.VizieR/VII/221
Title:
PSCz catalog
Short Name:
VII/221
Date:
21 Oct 2021
Publisher:
CDS
Description:
The PSCz survey consists of redshifts, infra-red and optical photometry, and assorted other information for 18351 IRAS sources, mostly selected from the Point Source Catalog. The survey was designed to select almost all galaxies with flux brighter than 0.595Jy at 60 microns, over the 84% of the sky with extinction small enough that reliable and complete optical identification and spectroscopy was possible. Some of the sources are not galaxies and some are multiple entries for the same galaxy as described below. There are in total 15411 galaxies or possible galaxies, for which redshifts are available for 14677. The galaxies without redshift are mostly distant or at low latitude, as described below. Many of these galaxies have now been observed as part of the BTP project (Saunders et al 1999, astro-ph/9909174 "The Behind the Plane Survey"), and their redshifts will be included in future revisions of the catalogue. The main catalogue is "pscz.dat". There is also a short version of the catalogue, "psczvs.dat", containing sufficient information for most studies. They correspond to the version 2.2.
2943. PS1 light curves and rotation periods of new asteroids
ID:
ivo://CDS.VizieR/J/AJ/159/25
Title:
PS1 light curves and rotation periods of new asteroids
Short Name:
J/AJ/159/25
Date:
21 Oct 2021
Publisher:
CDS
Description:
The intranight trajectories of asteroids can be approximated by straight lines, and so are their intranight detections. Therefore, the Hough transform, a line detecting algorithm, can be used to connect the line-up detections to find asteroids. We applied this algorithm to a high-cadence Pan-STARRS 1 (PS1) observation, which was originally designed to collect asteroid light curves for rotation period measurements. The algorithm recovered most of the known asteroids in the observing fields and, moreover, discovered 3574 new asteroids with magnitude mainly of 21.5<w_p1_<22.5mag. This magnitude range is equivalent to subkilometer main-belt asteroids (MBAs), which usually lack rotation period measurements due to their faintness. Using the light curves of the 3574 new asteroids, we obtained 122 reliable rotation periods, of which 13 are super-fast rotators (SRFs; i.e., rotation period of <2hr). The required cohesion to survive these SFRs range from tens to thousands of Pa, a value consistent with the known SFRs and the regolith on the Moon and Mars. The higher chance of discovering SFRs here suggests that subkilometer MBAs probably harbor more SFRs.
2944. PS1 photometry of 2863 ICRF3 quasars
ID:
ivo://CDS.VizieR/J/AJ/162/21
Title:
PS1 photometry of 2863 ICRF3 quasars
Short Name:
J/AJ/162/21
Date:
14 Mar 2022 06:53:33
Publisher:
CDS
Description:
We make use of individual (epoch) detection data from the Pan-STARRS "3{pi}" survey for 2863 optical ICRF3 counterparts in the five wavelength bands g, r, i, z, and y, published as part of the Data Release 2. A dedicated method based on the Functional Principal Component Analysis is developed for these sparse and irregularly sampled data. With certain regularization and normalization constraints, it allows us to obtain uniform and compatible estimates of the variability amplitudes and average magnitudes between the passbands and objects. We find that the starting assumption of affinity of the light curves for a given object at different wavelengths is violated for several percent of the sample. The distributions of rms variability amplitudes are strongly skewed toward small values, peaking at ~0.1mag with tails stretching to 2mag. Statistically, the lowest variability is found for the r band and the largest for the reddest y band. A small "brighter-redder" effect is present, with amplitudes in y greater than amplitudes in g in 57% of the sample. The variability versus redshift dependence shows a strong decline with z toward redshift 3, which we interpret as the time dilation of the dominant time frequencies. The colors of radio-loud ICRF3 quasars are correlated with redshift in a complicated, wavy pattern governed by the emergence of brightest emission lines within the five passbands.
2945. PS1 3{pi} RRab stars within the Sgr stream
ID:
ivo://CDS.VizieR/J/ApJ/850/96
Title:
PS1 3{pi} RRab stars within the Sgr stream
Short Name:
J/ApJ/850/96
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present a comprehensive and precise description of the Sagittarius (Sgr) stellar stream's 3D geometry as traced by its old stellar population. This analysis draws on the sample of ~44000 RR Lyrae (RRab) stars from the Pan-STARRS1 (PS1) 3{pi} survey, which is ~80% complete and ~90% pure within 80 kpc, and extends to >~120kpc with a distance precision of ~3% . A projection of RR Lyrae stars within |^~^B|_{sun}_<9{deg} of the Sgr stream's orbital plane reveals the morphology of both the leading and the trailing arms at very high contrast across much of the sky. In particular, the map traces the stream near- contiguously through the distant apocenters. We fit a simple model for the mean distance and line-of-sight depth of the Sgr stream as a function of the orbital plane angle ^~^{Lambda}_{sun}_, along with a power-law background model for the field stars. This modeling results in estimates of the mean stream distance precise to ~1% and it resolves the stream's line-of-sight depth. These improved geometric constraints can serve as new constraints for dynamical stream models.
2946. PS1 proper-motion survey for brown dwarfs. I. Taurus
ID:
ivo://CDS.VizieR/J/ApJ/858/41
Title:
PS1 proper-motion survey for brown dwarfs. I. Taurus
Short Name:
J/ApJ/858/41
Date:
21 Oct 2021
Publisher:
CDS
Description:
We are conducting a proper-motion survey for young brown dwarfs in the Taurus-Auriga molecular cloud based on the Pan-STARRS1 3{pi} Survey. Our search uses multi-band photometry and astrometry to select candidates, and is wider (370deg^2^) and deeper (down to ~3M_Jup_) than previous searches. We present here our search methods and spectroscopic follow-up of our high-priority candidates. Since extinction complicates spectral classification, we have developed a new approach using low-resolution (R~100) near-infrared spectra to quantify reddening-free spectral types, extinctions, and gravity classifications for mid-M to late-L ultracool dwarfs (<=100-3M_Jup_ in Taurus). We have discovered 25 low-gravity (VL-G) and the first 11 intermediate-gravity (INT-G) substellar (M6-L1) members of Taurus, constituting the largest single increase of Taurus brown dwarfs to date. We have also discovered 1 new Pleiades member and 13 new members of the Perseus OB2 association, including a candidate very wide separation (58kau) binary. We homogeneously reclassify the spectral types and extinctions of all previously known Taurus brown dwarfs. Altogether our discoveries have thus far increased the substellar census in Taurus by ~40% and added three more L-type members (<~5-10M_Jup_). Most notably, our discoveries reveal an older (>10Myr) low-mass population in Taurus, in accord with recent studies of the higher-mass stellar members. The mass function appears to differ between the younger and older Taurus populations, possibly due to incompleteness of the older stellar members or different star formation processes.
2947. PSR J1023+0038 VLT, XM and Swift observations
ID:
ivo://CDS.VizieR/J/A+A/631/A104
Title:
PSR J1023+0038 VLT, XM and Swift observations
Short Name:
J/A+A/631/A104
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report on a simultaneous near-infrared, optical, and X-ray campaign performed in 2017 with the XMM-Newton and Swift satellites and the HAWK-I instrument mounted on the Very Large Telescope (VLT) on the transitional millisecond pulsar PSR J1023+0038. Near-infrared observations were performed in fast-photometric mode (0.5s exposure time) in order to detect any fast variation of the flux and correlate this with the optical and X-ray light curves. The optical light curve shows the typical sinusoidal modulation at the system orbital period (4.75hr). No significant flaring or flickering is found in the optical, nor any signs of transitions between active and passive states. On the contrary, the near-infrared light curve displays a bimodal behaviour, showing strong flares in the first part of the curve, and an almost flat trend in the rest. The X-ray light curves instead show a few low-high mode transitions, but no flaring activity is detected. Interestingly, one of the low-high mode transitions occurs at the same time as the emission of an infrared flare. This can be interpreted in terms of the emission of an outflow or a jet: the infrared flare could be due to the evolving spectrum of the jet, which possesses a break frequency that moves from higher (near-infrared) to lower (radio) frequencies after the launching, which has to occur at the low-high mode transition. We also present the cross-correlation function between the optical and near-infrared curves. The near.infrared curve is bimodal, therefore we divided it into two parts (flaring and quiet). While the cross-correlation function of the quiet part is found to be flat, the function that refers to the flaring part shows a narrow peak at 10s, which indicates a delay of the near-infrared emission with respect to the optical. This lag can be interpreted as reprocessing of the optical emission at the light cylinder radius with a stream of matter spiraling around the system due to a phase of radio ejection. This strongly supports a different origin of the infrared flares that are observed for PSR J1023+0038 with respect to the optical and X-ray flaring activity that has been reported in other works on the same source.
2948. PS1 RRab stars for tracing outer Virgo overdensity
ID:
ivo://CDS.VizieR/J/ApJ/844/L4
Title:
PS1 RRab stars for tracing outer Virgo overdensity
Short Name:
J/ApJ/844/L4
Date:
21 Oct 2021
Publisher:
CDS
Description:
We report the detection of spatially distinct stellar density features near the apocenters of the Sagittarius (Sgr) stream's main leading and trailing arm. These features are clearly visible in a high-fidelity stellar halo map that is based on RR Lyrae from Pan-STARRS1: there is a plume of stars 10kpc beyond the apocenter of the leading arm, and there is a "spur" extending to 130kpc, almost 30kpc beyond the previously detected apocenter of the trailing arm. Such an apocenter substructure is qualitatively expected in any Sgr stream model, as stars stripped from the progenitor at different pericenter passages become spatially separated there. The morphology of these new Sgr stream substructures could provide much-needed new clues and constraints for modeling the Sgr system, including the level of dynamical friction that Sgr has experienced. We also report the discovery of a new, presumably unrelated halo substructure at 80kpc from the Sun and 10{deg} from the Sgr orbital plane, which we dub the outer Virgo overdensity.
2949. PS1 SNe Ia (0.02<z<0.7) griz light curves
ID:
ivo://CDS.VizieR/J/ApJ/795/44
Title:
PS1 SNe Ia (0.02<z<0.7) griz light curves
Short Name:
J/ApJ/795/44
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present griz_P1_ light curves of 146 spectroscopically confirmed Type Ia supernovae (SNe Ia; 0.03<z<0.65) discovered during the first 1.5yr of the Pan-STARRS1 Medium Deep Survey. The Pan-STARRS1 natural photometric system is determined by a combination of on-site measurements of the instrument response function and observations of spectrophotometric standard stars. We find that the systematic uncertainties in the photometric system are currently 1.2% without accounting for the uncertainty in the Hubble Space Telescope Calspec definition of the AB system. A Hubble diagram is constructed with a subset of 113 out of 146 SNe Ia that pass our light curve quality cuts. The cosmological fit to 310 SNe Ia (113 PS1 SNe Ia + 222 light curves from 197 low-z SNe Ia), using only supernovae (SNe) and assuming a constant dark energy equation of state and flatness, yields {omega}=-1.120_-0.206_^+0.360^(Stat)_-0.291_^+0.269^(Sys). When combined with BAO+CMB(Planck)+H_0_, the analysis yields {Omega}_M_=0.280_-0.012_^+0.013^ and {omega}=-1.166_-0.069_^+0.072^ including all identified systematics. The value of w is inconsistent with the cosmological constant value of -1 at the 2.3{sigma} level. Tension endures after removing either the baryon acoustic oscillation (BAO) or the H_0_ constraint, though it is strongest when including the H_0_ constraint. If we include WMAP9 cosmic microwave background (CMB) constraints instead of those from Planck, we find {omega}=-1.124_-0.065_^+0.083^, which diminishes the discord to <2{sigma}. We cannot conclude whether the tension with flat {Lambda}CDM is a feature of dark energy, new physics, or a combination of chance and systematic errors. The full Pan-STARRS1 SN sample with ~three times as many SNe should provide more conclusive results.
2950. 17 PS1 superluminous SNe LCs + classif. spectra
ID:
ivo://CDS.VizieR/J/ApJ/852/81
Title:
17 PS1 superluminous SNe LCs + classif. spectra
Short Name:
J/ApJ/852/81
Date:
21 Oct 2021
Publisher:
CDS
Description:
We present light curves and classification spectra of 17 hydrogen-poor superluminous supernovae (SLSNe) from the Pan-STARRS1 Medium Deep Survey (PS1 MDS). Our sample contains all objects from the PS1 MDS sample with spectroscopic classification that are similar to either of the prototypes SN 2005ap or SN 2007bi, without an explicit limit on luminosity. With a redshift range 0.3<z<1.6, PS1 MDS is the first SLSN sample primarily probing the high-redshift population; our multifilter PS1 light curves probe the rest- frame UV emission, and hence the peak of the spectral energy distribution. We measure the temperature evolution and construct bolometric light curves, and find peak luminosities of (0.5-5)x10^44^erg/s and lower limits on the total radiated energies of (0.3-2)x10^51^erg. The light curve shapes are diverse, with both rise and decline times spanning a factor of ~5 and several examples of double-peaked light curves. When correcting for the flux-limited nature of our survey, we find a median peak luminosity at 4000{AA} of M_4000_=-21.1mag and a spread of {sigma}=0.7mag.