- ID:
- ivo://CDS.VizieR/J/ApJ/892/105
- Title:
- Fourth catalog of Fermi LAT-detected AGNs (4LAC)
- Short Name:
- J/ApJ/892/105
- Date:
- 17 Jan 2022 00:31:09
- Publisher:
- CDS
- Description:
- The fourth catalog of active galactic nuclei (AGNs) detected by the Fermi Gamma-ray Space Telescope Large Area Telescope (4LAC) between 2008 August 4 and 2016 August 2 contains 2863 objects located at high Galactic latitudes (|b|>10{deg}). It includes 85% more sources than the previous 3LAC catalog based on 4yr of data. AGNs represent at least 79% of the high-latitude sources in the fourth Fermi-Large Area Telescope Source Catalog (4FGL), which covers the energy range from 50MeV to 1TeV. In addition, 344 gamma-ray AGNs are found at low Galactic latitudes. Most of the 4LAC AGNs are blazars (98%), while the remainder are other types of AGNs. The blazar population consists of 24% Flat Spectrum Radio Quasars (FSRQs), 38% BL Lac-type objects, and 38% blazar candidates of unknown types (BCUs). On average, FSRQs display softer spectra and stronger variability in the gamma-ray band than BL Lacs do, confirming previous findings. All AGNs detected by ground-based atmospheric Cerenkov telescopes are also found in the 4LAC.
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- ID:
- ivo://CDS.VizieR/I/143
- Title:
- Fourth Fundamental Cat and Suppl (FK4, FK4S)
- Short Name:
- I/143
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The FK4 was an attempt to establish a fundamental system of stellar positions and proper motions for the 1950 equinox using as much position data as were available. Most of the stars are brighter than 7.0 mag. To increase the star density in some regions of the sky, positions and proper motions for additional stars were established on the same system. This catalog contains seven data files, six for different equinoxes (1950, 1955, 1960, 1965, 1970, and 1975) and one for the supplemental stars. The 1950 and 1975 files contain the complete FK4 catalog (1535 stars); the others contain only 52 polar stars. In addition to a header record, the primary catalog contains for each star an identification number; the magnitude (maximum for a variable star); a variability flag, the minimum magnitude for a variable or the magnitude of the secondary for a double star; the HD spectral type and the type for the companion or a second type for a variable star; the position and the change and acceleration of the position; the proper motion and its change with time; the mean epoch of the observations for both right ascension and declination; the standard deviations of the position and proper motion; the numbers of the star in the Boss General Catalog, the N30 catalog, and in the Durchmusterungs; and the parallax. The supplement has a flag to indicate duplicity but no information about variability or the second component. It has no information about the temporal change of the position and proper motion and does not list the N30 and Durchmusterung numbers. It also omits the mean epoch for the observations.
- ID:
- ivo://CDS.VizieR/J/A+A/377/801
- Title:
- Fourth list of the Karachentsev catalog
- Short Name:
- J/A+A/377/801
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents HI observations of 165 dwarf galaxy candidates from the Karachentsev catalog of candidates for nearby dwarf galaxies prepared from film copies of POSSII and the ESO/SERC southern extension. Now a total of 601 galaxies from the published Karachentsev catalog have been searched for HI emission. Table 1 lists coordinates and general optical properties while Table 2 presents HI data and some global properties of these galaxies.
- ID:
- ivo://CDS.VizieR/I/182
- Title:
- Fourth Preliminary Catalogue of Stars
- Short Name:
- I/182
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Using the data observed with the Photoelectric Astrolabe Mark II of the Beijing Astronomical Observatory (PPA) during the period from 1982 to 1990, the Fourth Preliminary Catalogue of Stars (PACP4) have been Compiled. It consists of 1969 stars including 650 FK5 stars and 1319 GC stars. The mean precisions of position corrections in right ascension and declination are 4.1 ms and 0.067", respectively. The declinations are from +11 deg to +69 deg. The magnitudes are from 0.1 to 7.3. The mean epoch of observations is 1986.8.
- ID:
- ivo://CDS.VizieR/J/other/PBeiO/17.120
- Title:
- Fourth preliminary catalogue of stars
- Short Name:
- J/other/PBeiO/17
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- On the photon counter data observed with Photoeleetric Transit Instrument of Beijing Astronomical Observatory during the period from 1988 to 1990, corrections of right ascensions of 324 stars are given. The mean precision (<m_{DELTA}{alpha}cos{delta}_>) is 4.7ms. The mean observational epoch is 1989.7. The relations of residuals with magnitudes and spectral types are discussed and given respectively. Finally the systematic corrections (PPCP4-FK4) are also analysed.
- ID:
- ivo://CDS.VizieR/IX/4
- Title:
- Fourth UHURU Catalogue (4U)
- Short Name:
- IX/4
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The Fourth Uhuru (4U) Catalog lists 339 X-ray sources that were observed with the Uhuru (SAS A) X-ray observatory. It contains positional information in the form of 90% confidence level error boxes, 2-6keV intensities, possible optical and radio counterparts, and alternative names for sources observed in earlier compilations. The major classes of identified objects include binary stellar systems, supernova remnants, Seyfert galaxies, clusters of galaxies, and possibly the new class of superclusters of galaxies. The Uhuru satellite was a scanning X-ray instrument with a narrow (1 by 10 degree FWFM) and a wide (10 by 10 degree FWFM) collimator (cf. Giacconi et al. 1971ApJ...165L..27G). Typically, the scan rate was 0.5degree/second, with the spin axis in one position for roughly one day. During the interval for which the spin axis was fixed, repeated scans were made of the same 10 by 360 degrees band of the sky. For this catalog, the individual scans were superposed using aspect data from an orthogonally mounted triad of magnetometers and a Sun sensor onboard the spacecraft, supplemented by observations of well-located X-ray sources. The observations employed in producing this catalog were obtained over a total of 429 days between 1970 December 12 and 1973 March 18, apart from a gap between 1972 July and December when the spacecraft's transmitter was operating improperly.
- ID:
- ivo://CDS.VizieR/J/AJ/131/1872
- Title:
- Fourth VLBA calibrator survey: VCS4
- Short Name:
- J/AJ/131/1872
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents the fourth extension to the VLBA Calibrator Survey, containing 258 new sources not previously observed with very long baseline interferometry (VLBI). This survey, based on three 24hr Very Long Baseline Array observing sessions, fills remaining areas on the sky above declination -40{deg} where the calibrator density is less than one source within a 4{deg} radius disk in any given direction. The share of these areas was reduced from 4.6% to 1.9%. Source positions were derived from astrometric analysis of group delays determined at 2.3 and 8.6GHz frequency bands using the Calc/Solve software package. The VCS4 catalog of source positions, plots of correlated flux density versus projected baseline length, contour plots, and fits files of naturally weighted CLEAN images, as well as calibrated visibility function files, are available online at http://vlbi.gsfc.nasa.gov/vcs4 .
- ID:
- ivo://CDS.VizieR/J/MNRAS/420/2580
- Title:
- Four transits of HAT-P-13
- Short Name:
- J/MNRAS/420/2580
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometry of four transits of the planetary system HAT-P-13, obtained using defocused telescopes. We analyse these, plus nine data sets from the literature, in order to determine the physical properties of the system. The mass and radius of the star are M_A_=1.320+/-0.048+/-0.039M_{sun}} and R_A_=1.756+/-0.043+/-0.017R_{sun}_ (statistical and systematic error bars). We find the equivalent quantities for the transiting planet to be M_b_=0.906+/-0.024+/-0.018M_Jup_ and R_b_=1.487+/-0.038+/-0.015R_Jup_, with an equilibrium temperature of T'_eq_=1725+/-31K. Compared to previous results, which were based on much sparser photometric data, we find the star to be more massive and evolved, and the planet to be larger, hotter and more rarefied.
- ID:
- ivo://CDS.VizieR/J/ApJ/652/1715
- Title:
- Four transits of the exoplanet XO-1b
- Short Name:
- J/ApJ/652/1715
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present RIz photometry of four consecutive transits of the newly discovered exoplanet XO-1b. We improve on the estimates of the transit parameters, finding the planetary radius to be R_P_=1.184^0.028^_0.018_R_J_, and the stellar radius to be R*=0.928^+0.018^_0.013_R_{sun}_, assuming a stellar mass of M*=(1.00+/-0.03)M_{sun}_.
6480. Four transits of WASP-4b
- ID:
- ivo://CDS.VizieR/J/ApJ/733/127
- Title:
- Four transits of WASP-4b
- Short Name:
- J/ApJ/733/127
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present photometry of four transits of the exoplanet WASP-4b, each with a precision of approximately 500ppm and a time sampling of 40-60s. We have used the data to refine the estimates of the system parameters and ephemerides. During two of the transits we observed a short-lived, low-amplitude anomaly that we interpret as the occultation of a starspot by the planet. We also found evidence for a pair of similar anomalies in previously published photometry. The recurrence of these anomalies suggests that the stellar rotation axis is nearly aligned with the orbital axis, or else the starspot would not have remained on the transit chord. By analyzing the timings of the anomalies we find the sky-projected stellar obliquity to be {lambda}=-1^+14^_-12_degrees. This result is consistent with (and more constraining than) a recent observation of the Rossiter-McLaughlin effect. It suggests that the planet migration mechanism preserved the initially low obliquity, or else that tidal evolution has realigned the system. Future applications of this method using data from the CoRoT and Kepler missions will allow spin-orbit alignment to be probed for many other exoplanets.