- ID:
- ivo://CDS.VizieR/VIII/104
- Title:
- SPECFIND V3.0 Catalog of radio continuum spectra
- Short Name:
- VIII/104
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- Many radio continuum catalogs with different sensitivity limits and spatial resolutions are published via the VizieR database. Because of the diversity of spatial resolution, the cross-identification of individual sources is complex. By assuming a power-law spectrum, the SPECFIND tool is able to handle radio surveys at different frequencies from different instruments and different resolutions. Since the former version of the SPECFIND catalog was released ten years ago, hundreds of new radio continuum catalogs have been published. We upgraded the SPECFIND tool to reach a wider frequency range, especially the lower-frequency radio regime, as well as to have better spatial sky coverage. We adapted special selection criteria to all radio tables listed in VizieR to define a final sample of new catalogs. We implemented the new catalogs into the SPECFIND tool by unifying them and then compare the results to the last version. Furthermore we present and investigate sources with spectral breaks around 1.4GHz and around 325MHz. By increasing the number of implemented SPECFIND catalogs from 115 to 204, we improve the number of resulting spectra from 107500 to 340000 and increase the number of cross-identified sources from 600000 to 1.6 million. Furthermore, we present two samples of spectral break sources. The first sample includes 3104 spectral break sources with turnover frequencies around 1.4GHz, the second sample includes 18075 spectral break sources with turnover frequencies around 325MHz. Both samples include concave sources and Gigaherz-Peaked Spectrum (GPS) or Megaherz-Peaked Spectrum (MPS) sources. The SPECFIND V3.0 catalog is a very useful resource and a powerful open access tool, reachable via VizieR. By tripling the resulting spectra and including many radio continuum surveys from the last 50 years, we provide a significantly extended catalog of cross-identified radio continuum sources. Furthermore, the SIMBAD database will be updated using the SPECFIND V3.0 catalog and will contain more radio continuum data, serving the needs of future projects.
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Search Results
- ID:
- ivo://CDS.VizieR/VIII/85A
- Title:
- SPECFIND V2.0 Catalog of radio continuum spectra
- Short Name:
- VIII/85A
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This is the second release of the SPECFIND catalogue. For the radio cross-identification we included 3.76 million sources from 105 VizieR radio catalogues. The SPECFIND V2.0 catalogue contains about 107000 physical objects with associated radio spectra. With an increase of 8% of available sources with respect to the first release, we could increase the number of radio objects by 60%. The results of the spectrum identification process are provided as a master table, where a spectrum is attached to each radio source. Due to the SPECFIND algorithm, different radio sources of the same physical object can have somewhat different slopes and zero-points. We also present radio sources from positional cross-identification only taking into account the source extent and the survey resolution (overlapping beams or extents). The source flux densities were not taken into account as it was done for the SPECFINDV2.0 catalogue. In this sense, it represents the waste basket of SPECFINDV2.0.
- ID:
- ivo://CDS.VizieR/J/ApJ/884/L31
- Title:
- Spectra & HST obs. of gal. in 1ES1553+113 field
- Short Name:
- J/ApJ/884/L31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The relationship between galaxies and the state/chemical enrichment of the warm-hot intergalactic medium (WHIM) expected to dominate the baryon budget at low-z provides sensitive constraints on structure formation and galaxy evolution models. We present a deep redshift survey in the field of 1ES1553+113, a blazar with a unique combination of ultraviolet (UV)+X-ray spectra for surveys of the circumgalactic/intergalactic medium (CGM/IGM). Nicastro+ (2018Natur.558..406N) reported the detection of two OVII WHIM absorbers at z=0.4339 and 0.3551 in its spectrum, suggesting that the WHIM is metal rich and sufficient to close the missing baryons problem. Our survey indicates that the blazar is a member of a z=0.433 group and that the higher-z OVII candidate arises from its intragroup medium. The resulting bias precludes its use in baryon censuses. The z=0.3551 candidate occurs in an isolated environment 630kpc from the nearest galaxy (with stellar mass logM_*_/M_{sun}_~9.7), which we show is unexpected for the WHIM. Finally, we characterize the galactic environments of broad HI Ly{alpha} absorbers (Doppler widths of b=40-80km/s; T<~4x10^5^K) that provide metallicity-independent WHIM probes. On average, broad Ly{alpha} absorbers are ~2x closer to the nearest luminous (L>0.25L*) galaxy (700kpc) than narrow (b<30km/s; T<~4x10^5^K) ones (1300kpc) but ~2x further than OVI absorbers (350kpc). These observations suggest that gravitational collapse heats portions of the IGM to form the WHIM, but with feedback that does not enrich the IGM far beyond galaxy/group halos to levels currently observable in UV/X-ray metal lines.
- ID:
- ivo://CDS.VizieR/J/ApJ/664/458
- Title:
- Spectral fit of ULX sources
- Short Name:
- J/ApJ/664/458
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Data from Chandra observations of 30 nearby galaxies were analyzed and 365 X-ray point sources were chosen whose spectra were not contaminated by excessive diffuse emission and not affected by photon pileup. The spectra of these sources were fitted using two spectral models (an absorbed power-law and a disk blackbody) to ascertain the dependence of estimated parameters on the spectral model used. It was found that the cumulative luminosity function depends on the choice of the spectral model, especially for luminosities >10^40^ergs/s. A large number (~80) of the sources have luminosities >10^39^ergs/s (ultraluminous X-ray sources) with indistinguishable average spectral parameters (inner disk temperature ~1keV and/or photon index GAMMA~2) with those of the lower luminosity ones.
- ID:
- ivo://CDS.VizieR/J/MNRAS/444/2456
- Title:
- Spectral galaxy pairs from SDSS DR9
- Short Name:
- J/MNRAS/444/2456
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectral galaxy pairs (hereafter as SGPs) are composite galaxy spectra that contain two independent redshift systems. These spectra are useful for studying the dust properties of the foreground galaxies. In this article, a total of 165 spectra of SGPs are mined from the Sloan Digital Sky Survey (SDSS) Data Release 9 (DR9) using the concept of 'membership degree' from fuzzy set theory, especially defined to be suitable for fuzzy identification of emission lines. The spectra and images of this sample are classified according to their membership degree and image features, respectively. Many of the second redshift systems are too small or too dim to select from SDSS images alone, making the sample a potentially unique source of information on dust effects in low-luminosity or low surface brightness galaxies, which are underrepresented in morphological pair samples. The dust extinction of those objects with high membership degree is also estimated by Balmer decrement. Additionally, analyses for a series of spectroscopic observations of one SGP from 165 systems indicate that a newly star-forming region of our Milky Way might exist.
- ID:
- ivo://CDS.VizieR/J/A+A/423/133
- Title:
- Spectral indexes in HII galaxies
- Short Name:
- J/A+A/423/133
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We analyse the stellar content of a large number of HII galaxies from the continua and absorption features of their spectra using population synthesis methods, in order to gain information about the star formation histories of these objects. We find that all galaxies of our sample contain an old stellar population (>=1Gyr) that dominates the stellar mass, and in a majority of these we also found evidence for an intermediate-age population >=50Myr apart from the presently bursting, ionizing young generation <=10^7^yr.
- ID:
- ivo://CDS.VizieR/J/AZh/71/200
- Title:
- Spectral Investigation of NGC 7469
- Short Name:
- J/AZh/71/200
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This investigation is mainly related to hydrogen lines in the spectrum of NGC 7469 from the 1972-1990 data obtained using an image tube on the 2.6-m telescope of the Crimean Astrophysical Observatory. The decomposition of the hydrogen lines into broad and narrow components was performed. Variations in the intensities and broad-component contours were observed. One third of the spectrograms showed a broad, symmetric Ha line, while the others showed asymmetry: the blue wings fall more steeply than the red ones. The degree of asymmetry is variable, but no correlation between it and the brightness of the nucleus was found. This asymmetry becomes weaker when passing to higher members of the Balmer series. The halfwidths of the broad components increase from Ha to H{gamma}. Redshifts of broad components with respect to narrow ones might also be larger for higher members of the Balmer series. Intensities of the broad hydrogen lines follow continuum variations with a delay of about 28 days. The Balmer decrement for broad lines is much flatter than for narrow ones.
- ID:
- ivo://CDS.VizieR/J/MNRAS/448/1541
- Title:
- Spectral parameters for Mrk 335 and Ark 564
- Short Name:
- J/MNRAS/448/1541
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present a comprehensive flux-resolved spectral analysis of the bright narrow-line Seyfert 1 AGNs, Mrk 335 and Ark 564 using observations by XMM-Newton satellite. The mean and the flux-resolved spectra are fitted by an empirical model consisting of two Comptonization components, one for the low-energy soft excess and the other for the high-energy power law. A broad iron line and a couple of low-energy edges are required to explain the spectra. For Mrk 335, the 0.3-10 keV luminosity relative to the Eddington value, L_X_/L_Edd_, varied from 0.002 to 0.06. The index variation can be empirically described as {Gamma}=0.6log_10_L_X_/L_Edd_+3.0 for 0.005<L_X_/L_Edd_<0.04. At L_X_/L_Edd_~0.04 the spectral index changes and then continues to follow {Gamma}=0.6log_10_L_X_/L_Edd_+2.7, i.e. on a parallel track. We confirm that the result is independent of the specific spectral model used by fitting the data in the 3-10 keV band by only a power law and an iron line. For Ark 564, the index variation can be empirically described as {Gamma}=0.2log_10_L_X_/L_Edd_+2.7 with a significantly large scatter as compared to Mrk 335. Our results indicate that for Mrk 335, there may be accretion disc geometry changes which lead to different parallel tracks. These changes could be related to structural changes in the corona or enhanced reflection at high flux levels. There does not seem to be any homogeneous or universal relationship for the X-ray index and luminosity for different AGNs or even for the same AGN.
- ID:
- ivo://CDS.VizieR/J/A+A/285/812
- Title:
- Spectral properties of X-ray extragal. sources
- Short Name:
- J/A+A/285/812
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- (no description available)
- ID:
- ivo://CDS.VizieR/J/A+AS/131/295
- Title:
- Spectral survey of Case emission-line galaxies
- Short Name:
- J/A+AS/131/295
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The results of the follow-up spectroscopy of 178 emission-line galaxy (ELG) candidates from the Case objective-prism survey and nine Markarian galaxies with the 6m telescope are described. Only the candidates classified in the Case survey as those with emission lines were observed with the aim to form a statistical sample of blue compact galaxies (BCGs) with strong emission lines in the zone RA: 8h-16h, and DE: =+29deg-+38deg. We present the redshifts, equivalent widths and flux ratios for the strongest lines and the spectrum type for most of the galaxies with detected emission lines. A significant fraction (about 23%) of the observed Case galaxies do not show emission lines in blue. Preliminary analysis of the data is presented and the properties of the observed ELGs are compared with those of other known samples.
