- ID:
- ivo://CDS.VizieR/J/ApJ/829/119
- Title:
- Known pulsars identified in the TGSS ADR
- Short Name:
- J/ApJ/829/119
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have used the 150MHz radio continuum survey (TGSS ADR) from the Giant Metrewave Radio Telescope (GMRT) to search for phase-averaged emission toward all well-localized radio pulsars north of -53{deg} decl. We detect emission toward 200 pulsars with high confidence (>=5{sigma}) and another 88 pulsars at fainter levels. We show that most of our identifications are likely from pulsars, except for a small number where the measured flux density is confused by an associated supernova or pulsar-wind nebula, or a globular cluster. We investigate the radio properties of the 150MHz sample and find an unusually high number of gamma-ray binary millisecond pulsars with very steep spectral indices. We also note a discrepancy in the measured flux densities between GMRT and LOFAR pulsar samples, suggesting that the flux density scale for the LOFAR pulsar sample may be in error by approximately a factor of two. We carry out a separate search of 30 well-localized gamma-ray, radio-quiet pulsars in an effort to detect a widening of the radio beam into the line of sight at lower frequencies. No steep-spectrum emission was detected either toward individual pulsars or in a weighted stack of all 30 images.
Number of results to display per page
Search Results
- ID:
- ivo://CDS.VizieR/J/AJ/131/1923
- Title:
- Known quasars in the QUEST Variability Survey
- Short Name:
- J/AJ/131/1923
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present variability and multiwavelength photometric information for the 933 known quasars in the QUEST Variability Survey (Cat. <II/266>). These quasars are grouped into variable and nonvariable populations based on measured variability confidence levels.
- ID:
- ivo://CDS.VizieR/J/MNRAS/426/2107
- Title:
- KNoWS pilot bright sample
- Short Name:
- J/MNRAS/426/2107
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- During 2010-11, the Medicina 32-m dish hosted the seven-feed 18-26.5GHz receiver built for the Sardinia Radio Telescope, with the goal to perform its commissioning. This opportunity was exploited to carry out a pilot survey at 20GHz over the area for {delta}>+72.3{deg}. This paper describes all the phases of the observations, as they were performed using new hardware and software facilities. The map-making and source extraction procedures are illustrated. A customized data reduction tool was used during the follow-up phase, which produced a list of 73 confirmed sources down to a flux density of 115mJy. The resulting catalogue, presented here, is complete above 200mJy. Source counts are in agreement with those provided by the Australia Telescope 20GHz (AT20G) survey. This pilot activity paves the way for a larger project, the K-band Northern Wide Survey (KNoWS), whose final aim is to survey the whole Northern hemisphere down to a flux limit of 50mJy (5{sigma}).
7694. KODIAQ DR2
- ID:
- ivo://CDS.VizieR/J/AJ/154/114
- Title:
- KODIAQ DR2
- Short Name:
- J/AJ/154/114
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present and make publicly available the second data release (DR2) of the Keck Observatory Database of Ionized Absorption toward Quasars (KODIAQ) survey. KODIAQ DR2 consists of a fully reduced sample of 300 quasars at 0.07<z_em_<5.29 observed with HIRES at high resolution (36000{<=}R{<=}103000). DR2 contains 831 spectra available in continuum normalized form, representing a sum total exposure time of ~4.9 megaseconds on source. These co-added spectra arise from a total of 1577 individual exposures of quasars taken from the Keck Observatory Archive (KOA) in raw form and uniformly processed. DR2 extends DR1 by adding 130 new quasars to the sample, including additional observations of QSOs in DR1. All new data in DR2 were obtained with the single-chip Tektronix TK2048 CCD configuration of HIRES in operation between 1995 and 2004. DR2 is publicly available to the community, housed as a higher level science product at the KOA and in the igmspec database (v03).
7695. KODIAQ DR1
- ID:
- ivo://CDS.VizieR/J/AJ/150/111
- Title:
- KODIAQ DR1
- Short Name:
- J/AJ/150/111
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present and make publicly available the first data release (DR1) of the Keck Observatory Database of Ionized Absorption toward Quasars (KODIAQ) survey. The KODIAQ survey is aimed at studying galactic and circumgalactic gas in absorption at high redshift, with a focus on highly ionized gas traced by O vi, using the HIRES spectrograph on the KeckI telescope. KODIAQ DR1 consists of a fully reduced sample of 170 quasars at 0.29<z_em_<5.29 observed with HIRES at high resolution (36000{<=}R{<=}103000) between 2004 and 2012. DR1 contains 247 spectra available in continuum normalized form, representing a sum total exposure time of ~1.6 megaseconds. These coadded spectra arise from a total of 567 individual exposures of quasars taken from the Keck Observatory Archive (KOA) in raw form and uniformly processed using a publicly available HIRES data reduction package. DR1 is publicly available to the community, housed as a higher level science product at the KOA. We will provide future data releases that make available additional quasars, including those with pre-2004 observations taken with the previous-generation HIRES detectors.
- ID:
- ivo://CDS.VizieR/J/AJ/161/45
- Title:
- KODIAQ DR3: 727 quasars (01.<zem<6.4) with ESI
- Short Name:
- J/AJ/161/45
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present and make publicly available the third data release (DR3) of the Keck Observatory Database of Ionized Absorption toward Quasars (KODIAQ) survey. KODIAQ DR3 consists of a fully reduced sample of 727 quasars at 0.1<zem<6.4 observed with the Echellette Sepctrograph and Imager at moderate resolution (4000<~R<~10000). DR3 contains 872 spectra available in flux calibrated form, representing a sum total exposure time of ~2.8 megaseconds. These coadded spectra arise from a total of 2753 individual exposures of quasars taken from the Keck Observatory Archive (KOA) in raw form and uniformly processed using a data reduction package made available through the XIDL distribution. DR3 is publicly available to the community, housed as a higher level science product at the KOA and in the igmspec database.
- ID:
- ivo://CDS.VizieR/J/A+A/597/A134
- Title:
- Kohonen selected E+A galaxies from SDSS DR7
- Short Name:
- J/A+A/597/A134
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We created and analysed a large sample of local (z<0.4) post-starburst (PSB) galaxies. In the colour-mass diagram, the PSB sample is clearly concentrated towards the region between the red and the blue cloud, in agreement with the idea that PSB galaxies represent the transitioning phase between actively and passively evolving galaxies. The relative frequency of distorted PSB galaxies is at least 57%, significantly higher than in a comparison sample. The search for active galactic nuclei (AGN) based on conventional selection criteria in the radio and MIR results in a low AGN fraction of 2-3%. We confirm an MIR excess in the mean SED of the PSB galaxy sample that may indicate hidden AGNs, though other sources are also possible.
- ID:
- ivo://CDS.VizieR/J/A+A/541/A77
- Title:
- Kohonen-selected unusual SDSS quasars
- Short Name:
- J/A+A/541/A77
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Large spectroscopic surveys have discovered very peculiar and hitherto unknown types of active galactic nuclei (AGN). Such rare objects may hold clues to the accretion history of the supermassive black holes at the centres of galaxies. We aim to create a sizeable sample of unusual quasars from the unprecedented spectroscopic database of the Sloan Digital Sky Survey (SDSS).
- ID:
- ivo://CDS.VizieR/J/A+A/615/A79
- Title:
- KOINet. Study of exoplanet systems via TTVs
- Short Name:
- J/A+A/615/A79
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- During its four years of photometric observations, the Kepler space telescope detected thousands of exoplanets and exoplanet candidates. One of Kepler's greatest heritages has been the confirmation and characterization of hundreds of multi-planet systems via transit timing variations (TTVs). However, there are many interesting candidate systems displaying TTVs on such long timescales that the existing Kepler observations are of insufficient length to confirm and characterize them by means of this technique. To continue with Kepler's unique work, we have organized the "Kepler Object of Interest Network" (KOINet), a multi-site network formed of several telescopes located throughout America, Europe, and Asia. The goals of KOINet are to complete the TTV curves of systems where Kepler did not cover the interaction timescales well, to dynamically prove that some candidates are true planets (or not), to dynamically measure the masses and bulk densities of some planets, to find evidence for non-transiting planets in some of the systems, to extend Kepler's baseline adding new data with the main purpose of improving current models of TTVs, and to build a platform that can observe almost anywhere on the northern hemisphere, at almost any time. KOINet has been operational since March 2014. Here we show some promising first results obtained from analyzing seven primary transits of KOI-0410.01, KOI-0525.01, KOI-0760.01, and KOI-0902.01, in addition to the Kepler data acquired during the first and second observing seasons of KOINet. While carefully choosing the targets we set demanding constraints on timing precision (at least 1 min) and photometric precision (as good as one part per thousand) that were achieved by means of our observing strategies and data analysis techniques. For KOI-0410.01, new transit data revealed a turnover of its TTVs. We carried out an in-depth study of the system, which is identified in the NASA Data Validation Report as a false positive. Among others, we investigated a gravitationally bound hierarchical triple star system and a planet-star system. While the simultaneous transit fitting of ground- and space-based data allowed for a planet solution, we could not fully reject the three-star scenario. New data, already scheduled in the upcoming 2018 observing season, will set tighter constraints on the nature of the system.
- ID:
- ivo://CDS.VizieR/J/AJ/153/117
- Title:
- KOIs companions from high-resolution imaging
- Short Name:
- J/AJ/153/117
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We report on 176 close (<2'') stellar companions detected with high-resolution imaging near 170 hosts of Kepler Objects of Interest (KOIs). These Kepler targets were prioritized for imaging follow-up based on the presence of small planets, so most of the KOIs in these systems (176 out of 204) have nominal radii <6R_{Earth}_. Each KOI in our sample was observed in at least two filters with adaptive optics, speckle imaging, lucky imaging, or the Hubble Space Telescope. Multi-filter photometry provides color information on the companions, allowing us to constrain their stellar properties and assess the probability that the companions are physically bound. We find that 60%-80% of companions within 1'' are bound, and the bound fraction is >90% for companions within 0.5''; the bound fraction decreases with increasing angular separation. This picture is consistent with simulations of the binary and background stellar populations in the Kepler field. We also reassess the planet radii in these systems, converting the observed differential magnitudes to a contamination in the Kepler bandpass and calculating the planet radius correction factor, X_R_=R_p_(true)/R_p_(single). Under the assumption that planets in bound binaries are equally likely to orbit the primary or secondary, we find a mean radius correction factor for planets in stellar multiples of X_R_=1.65. If stellar multiplicity in the Kepler field is similar to the solar neighborhood, then nearly half of all Kepler planets may have radii underestimated by an average of 65%, unless vetted using high-resolution imaging or spectroscopy.