This study investigates periodic modulation of the light curve of the RRc star TV Boo and its physical parameters based on photometric data. This phenomenon, known as the Blazhko effect, is quite rare among RRc stars. The frequency analysis based on the data gathered at the Masaryk University Observatory (MUO) and also using SuperWASP data revealed symmetrically structured peaks around the main pulsation frequency and its harmonics, which indicate two modulation components of the Blazhko period. The main modulation periodicity was found to be 9.7374+/-0.0054d. This is one of the shortest known Blazhko periods among RRc stars. The second modulation period (21.5+/-0.2d) causes changes of the Blazhko effect itself. Some indices show that TV Boo could be affected by long-term changes of the order of years. Basic physical parameters were estimated via an MUO V light-curve solution using Fourier parameters. TV Boo seems to be a low-metallicity star with [Fe/H]=-1.89.
We aim to obtain a spatially resolved measurement of velocity dispersions in the disk of TW Hya. We obtained images with high spatial and spectral resolution of the CO J=2-1, CN N=2-1 and CS J=5-4 emission with ALMA in Cycle 2. The radial distribution of the turbulent broadening was derived with two direct methods and one modelling approach. The first method requires a single transition and derives T_ex_ directly from the line profile, yielding a v_turb_. The second method assumes that two different molecules are co-spatial, which allows using their relative line widths for calculating T_kin_ and v_turb_. Finally we fitted a parametric disk model in which the physical properties of the disk are described by power laws, to compare our direct methods with previous values.
Measurements of the protoplanetary disk frequency in young star clusters of different ages indicate disk lifetimes <10Myr. However, our current knowledge of how mass accretion in young stars evolves over the lifespans of disks is subject to many uncertainties, especially at the lower stellar masses. In this study, we investigate ongoing accretion activity in the TW Hydrae association (TWA), the closest association of pre-main sequence stars with active disks. The age (8-10Myr) and the proximity of the TWA render it an ideal target to probe the final stages of disk accretion down to brown dwarf masses. The study is based on homogeneous spectroscopic data from 300nm to 2500nm, obtained synoptically with X-shooter, which allows simultaneous derivation of individual extinction, stellar parameters, and accretion parameters for each star. The continuum excess emission diagnostics is used to estimate the accretion luminosities and mass accretion rates of our disk-bearing targets, and the shape and intensity of permitted and forbidden emission lines are analyzed to probe the physics of the star-disk interaction environment.
We present two new catalogues of superclusters of galaxies out to a redshift of z=0.15, based on the Abell/ACO cluster redshift compilation maintained by one of us (HA). The first of these catalogues, the all-sky Main SuperCluster Catalogue (MSCC), is based on only the rich (A-) Abell clusters, and the second one, the Southern SuperCluster Catalogue (SSCC), covers declinations {delta}<-17{deg} and includes the supplementary Abell S-clusters. A tunable Friends-of-Friends algorithm was used to account for the cluster density decreasing with redshift and for different selection functions in distinct areas of the sky. We present the full list of Abell clusters used, together with their redshifts and supercluster memberships and including the isolated clusters. The SSCC contains about twice the number of superclusters than MSCC for {delta}<-17{deg}, which we found to be due to (1) new superclusters formed by A-clusters in their cores and surrounded by S-clusters (50%), (2) new superclusters formed by S-clusters only (40%), (3) redistribution of member clusters by fragmentation of rich (multiplicity m>15) superclusters (8%), and (4) new superclusters formed by the connection of A-clusters through bridges of S-clusters (2%). Power-law fits to the cumulative supercluster multiplicity function yield slopes of {alpha}=-2.0 and {alpha}=-1.9 for MSCC and SSCC, respectively. This power-law behaviour is in agreement with the findings for other observational samples of superclusters, but not with that of catalogues based on cosmological simulations.
We performed a search for eclipsing and dipping sources in the archive of the EXTraS project-a systematic characterization of the temporal behavior of XMM-Newton point sources. We discovered dips in the X-ray light curve of 3XMM J004232.1+411314, which has been recently associated with the hard X-ray source dominating the emission of M31. A systematic analysis of XMM-Newton observations revealed 13 dips in 40 observations (total exposure time of ~0.8Ms). Among them, four observations show two dips, separated by ~4.01hr. Dip depths and durations are variable. The dips occur only during low-luminosity states (L_0.2-12_<1x10^38^erg/s), while the source reaches L_0.2-12_~2.8x10^38^erg/s. We propose that this system is a new dipping low-mass X-ray binary in M31 seen at high inclination (60{deg}-80{deg}); the observed dipping periodicity is the orbital period of the system. A blue HST source within the Chandra error circle is the most likely optical counterpart of the accretion disk. The high luminosity of the system makes it the most luminous (not ULX) dipper known to date.
We discuss the radio, optical, and X-ray properties of two newly discovered, very X-ray luminous, distant clusters of galaxies. Both systems were noted as cluster candidates in a cross-correlation of data from the WENSS (<VIII/162>) radio survey and the ROSAT All-Sky Survey (<IX/10>). Follow-up observations performed by us and the Massive Cluster Survey (MACS) team confirmed both sources as distant galaxy clusters. The first cluster, MACS J0717.5+3745 at a redshift of z=0.5548, contains a very extended, steep-spectrum radio source offset from the cluster core, making it the most distant radio relic known. The second cluster, MACS J1621.3+3810 at z=0.465, is a strong cooling flow with a relatively weak central radio source. We present results from ROSAT High-Resolution Imager (HRI, Cat. <IX/28>) observations of both clusters as well as from optical imaging and VLA radio interferometry observations. Our discoveries demonstrate that distant clusters can be efficiently identified in a relatively shallow X-ray survey, that radio/X-ray selection is efficient, and that both cooling flow and non-cooling flow clusters are selected.
Two-Meter Radio Mini Survey (T-RaMiSu) of the Bootes Field
Short Name:
TRAMISUBOO
Date:
28 Feb 2025
Publisher:
NASA/GSFC HEASARC
Description:
This table contains results from wide-area, deep, high-resolution 153-MHz GMRT observations of the NOAO Bootes field, adding to the extensive, multi-wavelength data of this region. The observations, data reduction, and catalog construction and description are described in the reference paper. The seven pointings (listed in Table 2 of the reference paper) produced a final mosaic covering 30 square degrees with a resolution of 25". The rms noise is 2 mJy/beam in the center of the image, rising to 4-5 mJy/beam at the edges, with an average of 3 mJy/beam. Seventy-five per cent of the area has an rms < 4 mJy/beam. The extracted source catalog contains 1289 sources detected at 5 sigma at flux densities between 4.1 mJy and 7.3 Jy, of which 453 are resolved. The authors estimate the catalogue to be 92% reliable and 95% complete at an integrated flux density limit of 14 mJy. The flux densities and astrometry have been corrected for systematic errors. In their paper, the authors calculate the differential source counts which are in good agreement with those in the literature and provide an important step forward in quantifying the source counts at these low frequencies and low flux densities. The GMRT 153-MHz sources have been matched to the 1.4-GHz NVSS and 327-MHz WENSS catalogs and spectral indices were derived. The source catalog presented here is derived from seven 4 hour pointings with the GMRT at 153 MHz, centered on the NOAO Bootes field. The resulting 30 square degree image has a central noise level of 2 mJy/beam and a resolution of 25". This table contains entries for all 1289 detected 153-MHz radio sources as well as for the 160 Gaussian components of the 77 sources (71 doubles and 3 triples) which could be fit by multiple Gaussian components, making a total of 1449 entries. This table was created by the HEASARC in January 2013 based on the <a href="https://cdsarc.cds.unistra.fr/ftp/cats/J/A+A/549/A55">CDS Catalog J/A+A/549/A55</a> files table2.dat and table3.dat. This is a service provided by NASA HEASARC .
2MASS data were collected by uniformly scanning the entire sky in three
near-infrared bands to detect and characterize point sources brighter than
about 1 mJy in each band, with signal-to-noise ratio (SNR) greater than 10,
using a pixel size of 2.0". This achieves an 80,000-fold improvement in
sensitivity relative to earlier surveys.
2MASS used two new, highly-automated 1.3-m telescopes, one at Mt. Hopkins,
AZ, and one at CTIO, Chile. Each telescope is equipped with a three-channel
camera, each channel consisting of a 256 by 256 array of HgCdTe detectors,
capable of observing the sky simultaneously at J (1.25 microns),
H (1.65 microns), and K<sub>s</sub> (2.17 microns).
<p>2MASS images and other data products can be obtained at the <a href="https://irsa.ipac.caltech.edu/applications/2MASS/QL/">NASA/IPAC Infrared Science Archive</a> Provenance: The Two Micron All Sky Survey is a joint project of the University of
Massachusetts and the Infrared Processing and Analysis Center, funded by
the National Aeronautics and Space Administration and the National
Science Foundation.. This is a service of NASA HEASARC.
WFAU, Institute for Astronomy, University of Edinburgh
Description:
The Two Micron All Sky Survey (2MASS) will provide a uniform survey of the entire sky at three near-infrared wavebands: J(lambdaeff = 1.25 micrometers), H(lambdaeff = 1.65 micrometers), and Ks(lambdaeff = 2.16 micrometers). A major goal of the survey is to probe large scale structures in the Milky Way and in the Local Universe, exploiting the relatively high transparency of the interstellar medium in the near-infrared, and the high near-infrared luminosities of evolved low- and intermediate-mass stars.Home page at http://pegasus.phast.umass.edu/
WFAU, Institute for Astronomy, University of Edinburgh
Description:
The Two Micron All Sky Survey (2MASS) will provide a uniform survey of the entire sky at three near-infrared wavebands: J(lambdaeff = 1.25 micrometers), H(lambdaeff = 1.65 micrometers), and Ks(lambdaeff = 2.16 micrometers). A major goal of the survey is to probe large scale structures in the Milky Way and in the Local Universe, exploiting the relatively high transparency of the interstellar medium in the near-infrared, and the high near-infrared luminosities of evolved low- and intermediate-mass stars.Home page at http://pegasus.phast.umass.edu/
![To the extent possible under law, the publisher has waived all copyright and related or neighboring rights to GAVO's ADQL course. For details, see the `Creative Commons CC0 1.0 Public Domain dedication <http://creativecommons.org/publicdomain/zero/1.0/>`_. Of course, you should still give proper credit when using this data as required by good scientific practice. .. image:: /static/img/cc0.png :alt: [CC0]](/registry-search/?f%5Brights_facet%5D%5B%5D=To+the+extent+possible+under+law%2C+the+publisher+has+waived+all+copyright+and+related+or+neighboring+rights+to+GAVO%27s+ADQL+course.++For+details%2C+see+the+%60Creative+Commons+CC0+1.0+Public+Domain+dedication+%3Chttp%3A%2F%2Fcreativecommons.org%2Fpublicdomain%2Fzero%2F1.0%2F%3E%60_.++Of+course%2C+you+should+still+give+proper+credit+when+using+this+data+as+required+by+good+scientific+practice.%0A%0A..+image%3A%3A+%2Fstatic%2Fimg%2Fcc0.png%0A+++%3Aalt%3A+%5BCC0%5D%0A%0A&f%5BvalidationLevel_facet%5D%5B%5D=2){kind=link}