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J/AJ/153/157   Candidate ICRF flat-spectrum radio sources. III.   (Titov+, 2017)

Optical spectra of candidate International Celestial Reference Frame (ICRF) flat-spectrum radio sources. III. Titov O., Pursimo T., Johnston H.M., Stanford L.M., Hunstead R.W., Jauncey D.L., Zenere K.A. <Astron. J., 153, 157-157 (2017)> =2017AJ....153..157T (SIMBAD/NED BibCode)
ADC_Keywords: Radio sources ; QSOs ; Galaxies, radio ; BL Lac objects ; Spectroscopy ; Redshifts ; VLBI Keywords: BL Lacertae objects: general - galaxies: active - quasars: emission lines - radio continuum: general - reference systems Abstract: In extending our spectroscopic program, which targets sources drawn from the International Celestial Reference Frame (ICRF) Catalog, we have obtained spectra for ∼160 compact, flat-spectrum radio sources and determined redshifts for 112 quasars and radio galaxies. A further 14 sources with featureless spectra have been classified as BL Lac objects. Spectra were obtained at three telescopes: the 3.58m European Southern Observatory New Technology Telescope, and the two 8.2m Gemini telescopes in Hawaii and Chile. While most of the sources are powerful quasars, a significant fraction of radio galaxies is also included from the list of non-defining ICRF radio sources. Description: Spectroscopic observations were carried out at three optical facilities. We had a five-night observing run in Visitor Mode at the ESO 3.58m New Technology Telescope (NTT) in 2013 December (Proposal 092.A-0021 (A)) using the ESO Faint Object Spectrograph and Camera system with grism #13 covering the wavelength range 3685-9315Å. The seeing during observations was typically 0.5''-2.0'', with a spectral resolution of 21Å FWHM. Exposure times varied from 5 to 30 minutes depending on the magnitude of each target and current sky conditions. Wavelength calibration made use of HeNeAr comparison spectra, resulting in an rms accuracy of 0.5Å. A large number of targets were observed in Service Mode at the Gemini North and Gemini South 8.2m telescopes through the Poor Weather Program (Proposals GN-2012B-Q-127, GS-2013A-Q-99, GS-2014A-Q-93) using the Gemini Multi-Object Spectrograph (GMOS) system with grating R400 at each site. This grating covers 4500Å centered at 5200Å. The wavelength resolution was ∼15Å FWHM, and an exposure time of 20 minutes was used for all targets. Wavelength calibration used the spectra of a CuAr comparison lamp, giving an rms accuracy of 0.3Å. We present our spectroscopic results in the same format as our previous paper (Titov et al. 2013, Cat. J/AJ/146/10). The redshifts of 112 IVS objects are listed in Table1. Fourteen objects with good S/N and featureless spectra were classified as probable BL Lac objects. These objects are listed in Table2. An additional 23 targets had low S/N spectra that did not permit a confident spectral classification. These are listed in Table3. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file sources.dat 13 110 Observed IVS objects table1.dat 89 401 Observed emission lines table2.dat 48 14 Probable BL Lac objects table3.dat 48 22 Objects with low signal-to-noise spectra notes.dat 415 33 Notes on individual targets
See also: VII/259 : 6dF galaxy survey final redshift release (Jones+, 2009) I/323 : International Celestial Reference Frame 2, ICRF2 (Ma+, 2009) J/AJ/150/58 : VLBI ICRF2 (Fey+, 2015) J/AJ/146/10 : Spectroscopy of emission-line ICRF2 candidates (Titov+, 2013) J/A+A/559/A95 : Fitted proper motions for the DR solution (Titov+, 2013) J/A+A/529/A91 : Proper motions of 555 quasars from VLBI (Titov+, 2011) J/A+A/506/1477 : Radio source distribution (Titov+, 2009) Byte-by-byte Description of file: sources.dat
Bytes Format Units Label Explanations
1- 5 A5 --- --- [IVS B] 6- 13 A8 --- IVS International VLBI Service name (HHMM+DDd, B1950)
Byte-by-byte Description of file: table1.dat
Bytes Format Units Label Explanations
1- 5 A5 --- --- [IVS B] 6- 13 A8 --- IVS International VLBI Service name (HHMM+DDd, B1950) 15- 16 I2 h RAh Hour of Right Ascension (J2000) (G1) 18- 19 I2 min RAm Minute of Right Ascension (J2000) (G1) 21- 27 F7.4 s RAs Second of Right Ascension (J2000) (G1) 29 A1 --- DE- Sign of the Declination (J2000) (G1) 30- 31 I2 deg DEd Degree of Declination (J2000) (G1) 33- 34 I2 arcmin DEm Arcminute of Declination (J2000) (G1) 36- 41 F6.3 arcsec DEs Arcsecond of Declination (J2000) (G1) 43- 45 A3 --- Tel Abbreviation of the telescope used for the spectrum (GS, GN, or NTT) (G2) 47- 56 A10 --- Line Line identifier 58- 63 F6.1 0.1nm Rlambda [1025.7/5175] Rest wavelength λ (in Å) 65- 70 F6.1 0.1nm Olambda [3730.5/9015.2] Observed wavelength λ (in Å) 71 A1 --- f_Olambda []] Flag ']' on Olambda when the line was not used for redshift determination 73- 78 F6.4 --- <z> [0.227/3.3] Mean spectroscopic redshift 80- 85 F6.4 --- e_<z> [0.0001/0.013] Uncertainty in z (1) 87 A1 --- f_<z> [S] Flag indicating a single-line redshift (2) 89 A1 --- n_IVS [N] Indicates a note in Section 3.1
Note (1): The quoted errors in the mean redshift were calculated as discussed in Titov et al. 2013 (Cat. J/AJ/146/10), i.e., from the quadratic combination of the scatter in the redshift estimates and the fractional error in the wavelength calibration. Note (2): Single-line redshifts, usually Mg II, are assigned an uncertainty of Δz=0.001 if the signal-to-noise ratio (S/N) is high, increasing to 0.003 for low S/N or a broad or asymmetric line.
Byte-by-byte Description of file: table[23].dat
Bytes Format Units Label Explanations
1- 5 A5 --- --- [IVS B] 6- 13 A8 --- IVS International VLBI Service name (HHMM+DDd, B1950) 15- 16 I2 h RAh Hour of Right Ascension (J2000) (G1) 18- 19 I2 min RAm Minute of Right Ascension (J2000) (G1) 21- 27 F7.4 s RAs Second of Right Ascension (J2000) (G1) 29 A1 --- DE- Sign of the Declination (J2000) (G1) 30- 31 I2 deg DEd Degree of Declination (J2000) (G1) 33- 34 I2 arcmin DEm Arcminute of Declination (J2000) (G1) 36- 41 F6.3 arcsec DEs Arcsecond of Declination (J2000) (G1) 43- 48 A6 --- Tel Telescope abbreviation (GS, GN, or NTT) (G2)
Byte-by-byte Description of file: notes.dat
Bytes Format Units Label Explanations
1- 5 A5 --- --- [IVS B] 6- 13 A8 --- IVS International VLBI Service name (HHMM+DDd, B1950) 15-415 A401 --- Note Notes on the source
Global Notes: Note (G1): Second Realization of the International Celestial Reference System (ICRF2; Ma et al. 2009, Cat. I/323; Fey et al. 2015, Cat. J/AJ/150/58) radio position. Note (G2): The telescope codes are defined as follows: GN = Gemini North; GS = Gemini South; NTT = ESO New Technology Telescope.
History: From electronic version of the journal References: Titov et al., Paper I. 2011AJ....142..165T Titov et al., Paper II. 2013AJ....146...10T, Cat. J/AJ/146/10
(End) Prepared by [AAS]; Sylvain Guehenneux [CDS] 01-Aug-2017
The document above follows the rules of the Standard Description for Astronomical Catalogues.From this documentation it is possible to generate f77 program to load files into arrays or line by line

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