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Krisztina Gabanyi - LBA observations for project V578 semester 2019OCTS
Blazars are radio-loud active galactic nuclei whose jets point very close to the line of sight. High-resolution VLBI observations can provide the ultimate evidence for the blazar nature of a source, by revealing the compact, bright, high brightness temperature core with flat radio spectrum. Zywucka et al. (2018) selected the blazar candidates from the Magellanic Quasar Survey. The selection method based mainly on the optical variability and the radio-loudness of the sources. Using the infrared color-color selection for blazars derived from the data of the WISE satellite by Massaro et al. (2012) we found that 10 of the 27 WISE-detected sources are outside of the blazar gamma-ray strip. We propose to observe 7 sources from these list and additional 7 sources as a control sample which fall within the blazar strip. We want to compare the mas-scale properties of the two samples to asses whether (i) additional criteria is needed select blazar sources (ii) and if yes the WISE color-color criteria is able to improve the selection method. Optical emission and variability is thought to be dominated by the beamed jet in blazars while in non-beamed (and not radio-loud) sources it originates in the accretion disks thus governed by accretion processes. Therefore, if the physical mechanism causing the optical variability is intended to be studies the nature of the variable source is important to be ascertained.
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Candidate Gamma-Ray Blazar Survey Source Catalog
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The authors have constructed a uniform all-sky survey of bright blazars, selected primarily by their flat radio spectra, that is designed to provide a large catalog of likely gamma-ray active galactic nuclei (AGNs). The defined sample, the Candidate Gamma-Ray Blazar Survey (CGRaBS) source catalog, has 1625 targets with radio and X-ray properties similar to those of the EGRET blazars, spread uniformly across the |b| > 10 degrees sky. They also report progress toward optical characterization of the sample; of objects with known red magnitude R < 23, 85% have been classified and 81% have measured redshifts. One goal of this program is to focus attention on the most interesting (e.g., high-redshift, high-luminosity, etc.) sources for intensive multi-wavelength study during the observations by the Large Area Telescope (LAT) on the Gamma-Ray Large-Area Space Telescope (GLAST) satellite observatory. This table was created by the HEASARC in April 2008 based on an electronic version of Table 2 of the reference paper obtained from the electronic ApJS web site. This is a service provided by NASA HEASARC .
Anna Kapinska - LBA observations for project V650 semester 2024APRS
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We request 8 GHz LBA observations of a nearby radio galaxy hosted by an active and likely unstable lenticular galaxy that may have underwent a minor merger in the past. Based on sub-arcsec resolution VLA observations, we propose to investigate the central 2 kpc region of the galaxy where we detected multi-component radio emission reminiscent of a relativistic jet but severely misaligned with the older large scale radio morphology (~80 deg reorientation). With this proposal we intend to verify if the detected central multi-component radio emission is indeed a relativistic jet as opposed to emission from star formation (or star bursts). This is a detection experiment and a pilot study. If the observations confirm that the radio emission is associated with a freshly launched realigned relativistic jet, a multi-epoch monitoring program will be designed and proposed in future semesters to characterise the emission and establish phenomenon at play causing the realignment.
COSMOS Field VLBA Observations 1.4-GHz Source Catalog
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This table contains the results of a project using wide-field Very Long Baseline Interferometry (VLBI) observations at 1.4 GHz of 2,865 known radio sources in the Cosmic Evolution Survey (COSMOS) field, a field which has exceptional multi-wavelength coverage. The main objective of this study is to identify the active galactic nuclei (AGN) in this field. Wide-field VLBI observations were made of all known radio sources in the COSMOS field at 1.4 GHz using the Very Long Baseline Array (VLBA). The authors also collected complementary multiwavelength information from the literature for the VLBA-detected sources.The combination of the number of sources, sensitivity, angular resolution and the area covered by this project are unprecedented. A catalog which contains the VLBI-detected sources is presented, the main purpose of which is to be used as an AGN catalog. the complementary multiwavelength (optical, infrared and X-ray) information of the VLBI-detected sources is also presented. The authors have detected 468 radio sources, expected to be AGN, with the VLBA. This is, to date, the largest sample assembled of VLBI-detected sources in the sub-mJy regime. They find a detection fraction of 20% +/- 1%, considering only those sources from the input catalog which were in principle detectable with the VLBA (2,361). As a function of the VLA flux density, the detection fraction is higher for higher flux densities, since at high flux densities a source could be detected even if the VLBI core accounts for a small percentage of the total flux density. As a function of redshift, the authors see no evolution of the detection fraction over the redshift range 0.5 < z < 3. In addition, they find that faint radio sources typically have a greater fraction of their radio luminosity in a compact core: ~70% of the sub-mJy sources detected with the VLBA have more than half of their total radio luminosity in a VLBI-scale component, whereas this is true for only ~30% of the sources that are brighter than 10 mJy. This suggests that fainter radio sources differ intrinsically from brighter ones. Across the entire sample, the authors find the predominant morphological classification of the host galaxies of the VLBA-detected sources to be early type (57%), although this varies with redshift and at z > 1.5 they find that spiral galaxies become the most prevalent (48%). The number of detections is high enough to study the faint radio population with statistically significant numbers. The authors demonstrate that wide-field VLBI observations, together with new calibration methods such as multi-source self-calibration and mosaicking, result in information which is difficult or impossible to obtain otherwise. This table contains 504 entries, including the 468 VLBA-detected sources and, for sources with multiple components, entries for the individual components. Among the detected sources, there are 452 single, 13 double, 2 triple and 1 quadruple source. Source entries have no suffix in their vlba_source_id, e.g., 'C3293', whereas component entries have a, b, c or d suffixes, e.g., 'C0090a' (and a value of 2 for the multi_cpt_flag parameter). This table was created by the HEASARC in December 2017 based on CDS Catalog J/A+A/607/A132 files vlba_cat.dat and vlba_mw.dat. This is a service provided by NASA HEASARC .
VLA A2390 Cluster of Galaxies 1.4-GHz Source Catalog
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This table contains the 1.4-GHz source catalog for the field of the cluster of galaxies A2390 as observed with the Very Large Array (VLA). This is one of the deepest radio images of a cluster field ever taken. The image covers an area of 34' x 34' with a synthesized beam of ~1.4" and a noise level of ~5.6 µJy (µJy) near the field center. In the reference paper, the authors construct differential number counts for the central regions (radius < 16') of this cluster, and find that the faint (S1.4GHz < 3 mJy) counts of A2390 are roughly consistent with the lowest blank field number counts. Their analyses indicate that the number counts are primarily from field radio galaxies. The authors suggest that the disagreement of their number counts for this cluster with those from a similarly deep observation of A370 that was also presented in the reference paper can be largely attributed to cosmic variance. The authors observed the A2390 cluster field with the VLA in the A configuration for ~31.4hr on-source during 2008 October. The field center is located at 21:53:36 +17:41:52 (J2000). This table was created by the HEASARC in August 2017 based on CDS Catalog J/ApJS/202/2/ file table2.dat. This file contained 699 entries for sources detected at 1.4 GHz in the A370 field, as well as 524 entries for sources detected at 1.4 GHz in the A2390 field. Only the latter are included in this HEASARC table, while the former can be found in the HEASARC's VLA3701P4 table. This is a service provided by NASA HEASARC .
VLA A370 Cluster of Galaxies 1.4-GHz Source Catalog
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This table contains the 1.4-GHz source catalog for the field of the cluster of galaxies A370 as observed with the Very Large Array (VLA). This is one of the deepest radio images of a cluster field ever taken. The image covers an area of 40' x 40' with a synthesized beam of ~1.7" and a noise level of ~5.7 µJy (µJy) near the field center. The authors have cataloged 200 redshifts for the A370 field. In the reference paper, they construct differential number counts for the central regions (radius < 16') of this cluster, and find that the faint (S1.4GHz < 3 mJy) counts of A370 are roughly consistent with the highest blank field number counts. Their analyses indicate that the number counts are primarily from field radio galaxies. The authors suggest that the disagreement of their number counts for this cluster with those from a similarly deep observation of A2390 that was also presented in the reference paper can be largely attributed to cosmic variance. The authors observed the A370 cluster field with the VLA in the A configuration for ~42.4hr on-source during 1999 August and September. K. S. Dwarakanath observed A370 in the B configuration for ~18.4hr on-source during 1994 August and September. The field center is located at 02:39:32 -01:35:07 (J2000). This is offset by approximately 5 arcminutes from the cluster center at 02:39:50.5 -01:35:08. The authors also targeted 58 radio sources, in A370, that had no existing optical spectral data using the Hydra fiber spectrograph on the Wisconsin-Indiana-Yale-NOAO (WIYN) telescope (spectral window of ~4500 - 9500 Angstrom). They preferentially targeted optically bright galaxies, obtaining these data in a single two-hour pointing on 2012 January 20. Of the 58 targets, the authors obtained high-confidence redshifts for 36. This table was created by the HEASARC in August 2017 based on CDS Catalog J/ApJS/202/2/ file table2.dat. This file contained 699 entries for sources detected at 1.4 GHz in the A370 field, as well as 524 entries for sources detected at 1.4 GHz in the A2390 field. Only the former are included in this HEASARC table, while the latter can be found in the HEASARC's VLA23901P4 table. This is a service provided by NASA HEASARC .
NGC 3115 Chandra X-Ray Point Source Catalog
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This table contains some of the results from an in-depth study of low-mass X-ray binaries (LMXBs) detected in the nearby lenticular galaxy NGC 3115 using the Megasecond Chandra X-ray Visionary Project observation (total exposure time 1.1 Ms). In total the authors found 136 candidate LMXBs in the field and 49 in globular clusters (GCs) above 2-sigma detection, with 0.3-8 keV luminosity LX ~ 1036 - 1039 erg s-1. Other than 13 transient candidates, the sources overall have less long-term variability at higher luminosity, at least at LX >~ 2 x 1037 erg s-1. In order to identify the nature and spectral state of these sources, the authors compared their collective spectral properties based on single-component models (a simple power law or a multicolor disk) with the spectral evolution seen in representative Galactic LMXBs. The authors found that in the LX vs. photon index GammaPL and LX versus disk temperature kTMCD plots, most of their sources fall on a narrow track in which the spectral shape hardens with increasing luminosity below LX ~ 7 x 1037 erg s-1, but is relatively constant (GammaPL ~ 1.5 or kTMCD ~ 1.5 keV) above this luminosity, which is similar to the spectral evolution of Galactic neutron star (NS) LMXBs in the soft state in the Chandra bandpass. Therefore, the authors identified the track as the NS LMXB soft-state track and suggested sources with LX <~ 1037 erg s-1 as atolls in the soft state and those with LX >~ 1037 erg s-1 as Z sources. Ten other sources (five are transients) displayed significantly softer spectra and are probably black hole X-ray binaries in the thermal state. One of them (a persistent source) is in a metal-poor GC. The 11 Chandra observations of NGC 3115 are listed in Table 1 of the reference paper. They were made during three epochs: one in 2001,two in 2010, and nine in 2012. All observations used the imaging array of the AXAF CCD Imaging Spectrometer (ACIS). This table contains the properties of the 482 detected point sources in the merged and single Chandra ACIS observations of NGC 3115 above a 2-sigma threshold and after eliminating a number of spurious sources associated with bright streaks on the ACIS-S1 chip and (in one case) on a CCD edge. 469 of these sources (indicated by values of obs_flag = '0') have a single entry in this table, based on their properties as derived from all of the available Chandra data for that position. There are 13 transient sources (having obs_flag = 'h') for which an additional entry is provided referring to their properties in the "high state", and based on the combination of their high-state observations, as shown in Figures 3(a) - 3(d) in the reference paper. For source number 198, there is a second additional entry provided referring to its properties in the "low state", and based on the combination of its low-state observations, as shown in Figure 3(c) in the reference paper. Thus, there are 496 entries (rows) in this table, i.e., 482 + 13 + 1. This table was created by the HEASARC in August 2015 based on the union of the machine-readable versions of Table 3 (the master source catalog) and Table 4 (the source counts, fluxes and hardness ratios in the merged observations) that were obtained from the ApJ web site. It does not contain the source counts and fluxes in the individual observations which were given in Table 5 of the reference paper. This is a service provided by NASA HEASARC .
Vishal Gajjar - Parkes observations for project PX600 semester 2020APRS 125
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The Galactic Center (GC) is a key target for the radio component of Breakthrough Listen (BL) program. Offering the largest amount of stars in any given direction in the sky, the GC is widely cited as a location believed to harbour advanced civilizations, and it is also the most energetic region in the Milky Way. We aim to conduct BL-GC Survey with Parkes radio telescope for around 350 hours. We will cover the frequency range from 700 MHz to 4 GHz, utilizing the newly installed ultra-wideband receiver. Our team has already leveraged both standard and bespoke tools to construct a flexible software stack to search data for signals of interest. We will look for signals from extraterrestrial intelligence (ETI) by searching for both simple narrow-band signals and complex modulated signals. Along with that, as an ancillary science, we will also search for accelerated pulsars — likely orbiting a supermassive black hole at the centre of the Milky Way Galaxy. Data products produced during this program will also be publically available to engage larger pulsar community
Vishal Gajjar - Parkes observations for project PX600 semester 2020APRS 116
공공데이터포털
The Galactic Center (GC) is a key target for the radio component of Breakthrough Listen (BL) program. Offering the largest amount of stars in any given direction in the sky, the GC is widely cited as a location believed to harbour advanced civilizations, and it is also the most energetic region in the Milky Way. We aim to conduct BL-GC Survey with Parkes radio telescope for around 350 hours. We will cover the frequency range from 700 MHz to 4 GHz, utilizing the newly installed ultra-wideband receiver. Our team has already leveraged both standard and bespoke tools to construct a flexible software stack to search data for signals of interest. We will look for signals from extraterrestrial intelligence (ETI) by searching for both simple narrow-band signals and complex modulated signals. Along with that, as an ancillary science, we will also search for accelerated pulsars — likely orbiting a supermassive black hole at the centre of the Milky Way Galaxy. Data products produced during this program will also be publically available to engage larger pulsar community
Vishal Gajjar - Parkes observations for project PX600 semester 2020APRS 133
공공데이터포털
The Galactic Center (GC) is a key target for the radio component of Breakthrough Listen (BL) program. Offering the largest amount of stars in any given direction in the sky, the GC is widely cited as a location believed to harbour advanced civilizations, and it is also the most energetic region in the Milky Way. We aim to conduct BL-GC Survey with Parkes radio telescope for around 350 hours. We will cover the frequency range from 700 MHz to 4 GHz, utilizing the newly installed ultra-wideband receiver. Our team has already leveraged both standard and bespoke tools to construct a flexible software stack to search data for signals of interest. We will look for signals from extraterrestrial intelligence (ETI) by searching for both simple narrow-band signals and complex modulated signals. Along with that, as an ancillary science, we will also search for accelerated pulsars — likely orbiting a supermassive black hole at the centre of the Milky Way Galaxy. Data products produced during this program will also be publically available to engage larger pulsar community