- ID:
- ivo://CDS.VizieR/J/ApJ/793/38
- Title:
- Palomar Transient Factory photometric observations
- Short Name:
- J/ApJ/793/38
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the results of a Palomar Transient Factory (PTF) archival search for blue transients that lie in the magnitude range between "normal" core-collapse and superluminous supernovae (i.e., with -21<=M_R(peak)_<=-19). Of the six events found after excluding all interacting Type IIn and Ia-CSM supernovae, three (PTF09ge, 09axc, and 09djl) are coincident with the centers of their hosts, one (10iam) is offset from the center, and a precise offset cannot be determined for two (10nuj and 11glr). All the central events have similar rise times to the He-rich tidal disruption candidate PS1-10jh, and the event with the best-sampled light curve also has similar colors and power-law decay. Spectroscopically, PTF09ge is He-rich, while PTF09axc and 09djl display broad hydrogen features around peak magnitude. All three central events are in low star formation hosts, two of which are E+A galaxies. Our spectrum of the host of PS1-10jh displays similar properties. PTF10iam, the one offset event, is different photometrically and spectroscopically from the central events, and its host displays a higher star formation rate. Finding no obvious evidence for ongoing galactic nuclei activity or recent star formation, we conclude that the three central transients likely arise from the tidal disruption of a star by a supermassive black hole. We compare the spectra of these events to tidal disruption candidates from the literature and find that all of these objects can be unified on a continuous scale of spectral properties. The accumulated evidence of this expanded sample strongly supports a tidal disruption origin for this class of nuclear transients.
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Search Results
- ID:
- ivo://CDS.VizieR/II/313
- Title:
- Palomar Transient Factory (PTF) photometric catalog 1.0
- Short Name:
- II/313
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We construct a photometrically calibrated catalog of non-variable sources from the Palomar Transient Factory (PTF) observations. The first version of this catalog presented here, the PTF photometric catalog 1.0, contains calibrated R_PTF_-filter magnitudes for ~2.1x10^7^ sources brighter than magnitude 19, over an area of ~11233{deg}^2^. The magnitudes are provided in the PTF photometric system, and the color of a source is required in order to convert these magnitudes into other magnitude systems. We estimate that the magnitudes in this catalog have typical accuracy of about 0.02mag with respect to magnitudes from the Sloan Digital Sky Survey. The median repeatability of our catalog's magnitudes for stars between 15 and 16mag, is about 0.01mag, and it is better than 0.03mag for 95% of the sources in this magnitude range. The main goal of this catalog is to provide reference magnitudes for photometric calibration of visible light observations. Subsequent versions of this catalog, which will be published incrementally online, will be extended to a larger sky area and will also include g_PTF_-filter magnitudes, as well as variability and proper motion information.
- ID:
- ivo://CDS.VizieR/J/ApJ/788/154
- Title:
- Palomar Transient Factory SNe IIn photometry
- Short Name:
- J/ApJ/788/154
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Interaction of supernova (SN) ejecta with the optically thick circumstellar medium (CSM) of a progenitor star can result in a bright, long-lived shock-breakout event. Candidates for such SNe include Type IIn and superluminous SNe. If some of these SNe are powered by interaction, then there should be a specific relation between their peak luminosity, bolometric light-curve rise time, and shock-breakout velocity. Given that the shock velocity during shock breakout is not measured, we expect a correlation, with a significant spread, between the rise time and the peak luminosity of these SNe. Here, we present a sample of 15 SNe IIn for which we have good constraints on their rise time and peak luminosity from observations obtained using the Palomar Transient Factory. We report on a possible correlation between the R-band rise time and peak luminosity of these SNe, with a false-alarm probability of 3%. Assuming that these SNe are powered by interaction, combining these observables and theory allows us to deduce lower limits on the shock-breakout velocity. The lower limits on the shock velocity we find are consistent with what is expected for SNe (i.e., ~10^4^ km/s). This supports the suggestion that the early-time light curves of SNe IIn are caused by shock breakout in a dense CSM. We note that such a correlation can arise from other physical mechanisms. Performing such a test on other classes of SNe (e.g., superluminous SNe) can be used to rule out the interaction model for a class of events.
- ID:
- ivo://CDS.VizieR/J/A+A/419/533
- Title:
- Pal 13 UBV, proper motions and radial velocities
- Short Name:
- J/A+A/419/533
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Recently, combining radial velocities from Keck/HIRES echelle spectra with published proper motion membership probabilities, Cote et al. (2002ApJ...574..783C) observed a sample of 21 stars, probable members of Palomar 13, a globular cluster in the Galactic halo. Their projected velocity dispersion sigma_p_=2.2+/-0.4km/s gives a mass-to-light ratio M/L_V_=40^+24^_-17_, about one order of magnitude larger than the usual estimate for globular clusters. We present here radial velocities measured from three different CCD frames of commissioning observations obtained with the new ESO/VLT instrument FLAMES (Fibre Large Array Multi Element Spectrograph). From these data, now publicly available, we measure the homogeneous radial velocities of eight probable members of this globular cluster. A new projected velocity dispersion sigma_p_=0.6-0.9+/-0.3km/s implies Palomar 13 mass-to-light ratio M/L_V_=3-7, similar to the usual value for globular clusters. We discuss briefly the two most obvious reasons for the previous unusual mass-to-light ratio finding: binaries, now clearly detected, and more homogeneous data from the multi-fibre FLAMES spectrograph.
- ID:
- ivo://mast.stsci/phat
- Title:
- Panchromatic Hubble Andromeda Treasury (PHAT)
- Short Name:
- PHAT
- Date:
- 23 Jul 2020 19:28:22
- Publisher:
- Space Telescope Science Institute Archive
- Description:
- The Panchromatic Hubble Andromeda Treasury is a Hubble Space Telescope Multi-cycle program to map roughly a third of M31's star forming disk, using 6 filters covering from the ultraviolet through the near infrared. With HST's resolution and sensitivity, the disk of M31 will be resolved into more than 100 million stars, enabling a wide range of scientific endeavors.
- ID:
- ivo://CDS.VizieR/J/ApJ/782/42
- Title:
- Panchromatic observations of PTF11qcj
- Short Name:
- J/ApJ/782/42
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present the discovery, classification, and extensive panchromatic (from radio to X-ray) follow-up observations of PTF11qcj, a supernova (SN) discovered by the Palomar Transient Factory (PTF). Our observations with the Karl G. Jansky Very Large Array show that this event is radio-loud: PTF11qcj reached a radio peak luminosity comparable to that of the famous gamma-ray-burst-associated SN 1998bw (L_5GHz_{approx}10^29^erg/s/Hz). PTF11qcj is also detected in X-rays with the Chandra Observatory, and in the infrared band with Spitzer. Our multi-wavelength analysis probes the SN interaction with circumstellar material. The radio observations suggest a progenitor mass-loss rate of ~10^-4^M_{sun}_/yr*(v_w_/1000km/s), and a velocity of {approx}0.3-0.5c for the fastest moving ejecta (at {approx}10 days after explosion). However, these estimates are derived assuming the simplest model of SN ejecta interacting with a smooth circumstellar wind, and do not account for possible inhomogeneities in the medium and asphericity of the explosion. The radio data show deviations from such a simple model, as well as a late-time re-brightening. The X-ray flux from PTF11qcj is compatible with the high-frequency extrapolation of the radio synchrotron emission (within the large uncertainties). A light echo from pre-existing dust is in agreement with our infrared data. Our pre-explosion data from the PTF suggest that a precursor eruption of absolute magnitude M_r_{approx}-13mag may have occurred {approx}2.5yr prior to the SN explosion. Overall, PTF11qcj fits the expectations from the explosion of a Wolf-Rayet star. Precursor eruptions may be a feature characterizing the final pre-explosion evolution of such stars.
- ID:
- ivo://CDS.VizieR/J/A+A/551/A100
- Title:
- Panchromatic SED of Herschel sources
- Short Name:
- J/A+A/551/A100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Combining far-infrared Herschel photometry from the PACS Evolutionary Probe (PEP) and Herschel Multi-tiered Extragalactic Survey (HerMES) guaranteed time programs with ancillary datasets in the GOODS-N, GOODS-S and COSMOS fields, it is possible to sample the 8-500 micron spectral energy distributions of galaxies with at least 7-10 bands. Extending to the UV, optical, and near- infrared, the number of bands increases up to 43. We reproduce the distribution of galaxies in a carefully selected 10 restframe color space, based on this rich data-set, using a superposition of multi-variate Gaussian modes. We use this model to classify galaxies and build median spectral energy distributions (SEDs) of each class, which are then fitted with a modified version of the MAGPHYS code that combines stellar light, emission from dust heated by stars and a possible warm dust contribution heated by an Active Galactic Nucleus (AGN). The color distribution of galaxies in each of the considered fields can be well described with the combination of 6-9 classes, spanning a large range of far- to near-IR luminosity ratios, as well as different strength of the AGN contribution to bolometric luminosities. The defined Gaussian grouping is used to identify rare or odd sources. The zoology of outliers includes Herschel-detected ellipticals, very blue z~1 Ly{alpha}-break galaxies, quiescent spirals, and torus-dominated AGN with star formation. Out of these groups and outliers, a new template library is assembled, consisting of 32 SEDs describing the intrinsic scatter in the restframe UV-to-submm colors of infrared galaxies. This library is tested against L(IR) estimates with and without Herschel data included, and compared to eight other popular methods often adopted in the literature. When implementing Herschel photometry, these approaches produce L(IR) values consistent with each other within a median absolute deviation of 10-20%, the scatter being dominated more by fine tuning of the codes, rather than by the choice of SED templates. Finally, the library is used to classify 24 micron detected sources in PEP GOODS fields on the basis of AGN content, L(60)/L(100) color and L(160)/L(1.6) luminosity ratio. AGN appear to be distributed in M*-SFR along with all other galaxies, regardless of the amount of infrared luminosity they are powering, with the tendency to lie on the high SFR side of the "main sequence". The incidence of warmer star-forming sources grows for objects with higher specific star formation rates, and they tend to populate the "off-sequence" region of the M*-SFR-z space.
- ID:
- ivo://CDS.VizieR/J/ApJ/776/80
- Title:
- PAndAS view of Andromeda satellites. I.
- Short Name:
- J/ApJ/776/80
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a generic algorithm to search for dwarf galaxies in photometric catalogs and apply it to the Pan-Andromeda Archaeological Survey (PAndAS). The algorithm is developed in a Bayesian framework and, contrary to most dwarf galaxy search codes, makes use of both the spatial and color-magnitude information of sources in a probabilistic approach. Accounting for the significant contamination from the Milky Way foreground and from the structured stellar halo of the Andromeda galaxy, we recover all known dwarf galaxies in the PAndAS footprint with high significance, even for the least luminous ones. Some Andromeda globular clusters are also recovered and, in one case, discovered. We publish a list of the 143 most significant detections yielded by the algorithm. The combined properties of the 39 most significant isolated detections show hints that at least some of these trace genuine dwarf galaxies, too faint to be individually detected. Follow-up observations by the community are mandatory to establish which are real members of the Andromeda satellite system. The search technique presented here will be used in an upcoming contribution to determine the PAndAS completeness limits for dwarf galaxies. Although here tuned to the search of dwarf galaxies in the PAndAS data, the algorithm can easily be adapted to the search for any localized overdensity whose properties can be modeled reliably in the parameter space of any catalog.
- ID:
- ivo://CDS.VizieR/J/A+A/644/A163
- Title:
- Pan-STARRS lens candidates from neural networks
- Short Name:
- J/A+A/644/A163
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a systematic search for wide-separation (with Einstein radius ~1.5"), galaxy-scale strong lenses in the 30000 sq.deg of the Pan-STARRS 3pi survey on the Northern sky. With long time delays of a few days to weeks, these types of systems are particularly well-suited for catching strongly lensed supernovae with spatially-resolved multiple images and offer new insights on early-phase supernova spectroscopy and cosmography. We produced a set of realistic simulations by painting lensed COSMOS sources on Pan-STARRS image cutouts of lens luminous red galaxies (LRGs) with redshift and velocity dispersion known from the sloan digital sky survey (SDSS). First, we computed the photometry of mock lenses in gri bands and applied a simple catalog-level neural network to identify a sample of 1050207 galaxies with similar colors and magnitudes as the mocks. Second, we trained a convolutional neural network (CNN) on Pan-STARRS gri image cutouts to classify this sample and obtain sets of 105760 and 12382 lens candidates with scores of pCNN>0.5 and >0.9, respectively. Extensive tests showed that CNN performances rely heavily on the design of lens simulations and the choice of negative examples for training, but little on the network architecture. The CNN correctly classified 14 out of 16 test lenses, which are previously confirmed lens systems above the detection limit of Pan-STARRS. Finally, we visually inspected all galaxies with pCNN>0.9 to assemble a final set of 330 high-quality newly-discovered lens candidates while recovering 23 published systems. For a subset, SDSS spectroscopy on the lens central regions proves that our method correctly identifies lens LRGs at z~0.1-0.7. Five spectra also show robust signatures of high-redshift background sources, and Pan-STARRS imaging confirms one of them as a quadruply-imaged red source at z_s_=1.185, which is likely a recently quenched galaxy strongly lensed by a foreground LRG at z_d_=0.3155. In the future, high-resolution imaging and spectroscopic follow-up will be required to validate Pan-STARRS lens candidates and derive strong lensing models. We also expect that the efficient and automated two-step classification method presented in this paper will be applicable to the ~4 mag deeper gri stacks from the Rubin Observatory Legacy Survey of Space and Time (LSST) with minor adjustments.
- ID:
- ivo://CDS.VizieR/J/A+A/559/A43
- Title:
- Pan-STARRS1 (PS1) observations of the Hyades
- Short Name:
- J/A+A/559/A43
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We performed a kinematic and photometric search for Hyades members using the PPMXL and Pan-STARRS1 sky surveys, up to 30pc from the cluster centre, down to masses of 0.1M_{sun}_. We exclude some candidates previously identified in Roeser et al. (2011, Cat. J/A+A/531/A92). We discovered 62 new Hyades member candidates with velocity perpendicular to the Hyades motion up to 4km/s. They have mass estimates between 0.43 and 0.09M_{sun}_, for a total mass of 10M_{sun}_.
