Access to Astronomical Catalogues

← Click to display the menu
J/ApJ/508/200       QSO low-z Lyα absorbers            (Tripp+, 1998)

The relationship between galaxies and low-redshift weak Lyα absorbers in the directions of H1821+643 and PG 1116+215. Tripp T.M., Lu L., Savage B.D. <Astrophys. J. 508, 200 (1998)> =1998ApJ...508..200T
ADC_Keywords: QSOs ; Redshifts ; Equivalent widths Keywords: galaxies: distances and redshifts - quasars: absorption lines - quasars: individual (H1821+643, PG 1116+215) Abstract: To study the nature of low-z Lyα absorbers in the spectra of QSOs, we have obtained high signal-to-noise ratio (S/N) UV spectra of H1821+643 (zem=0.297) and PG 1116+215 (zem=0.177) with the Goddard High-Resolution Spectrograph on the Hubble Space Telescope. File Summary:
FileName Lrecl Records Explanations
ReadMe 80 . This file table1.dat 57 154 Redshifts of galaxies in the field of H1821+643 table2.dat 57 118 Redshifts of galaxies in the field of PG 1116+215 table4.dat 67 54 Absorption lines detected in the GHRS G140L spectrum of H1821+643 table5.dat 61 31 Absorption lines detected in the GHRS G140L spectrum of PG 1116+215
Byte-by-byte Description of file: table1.dat table2.dat
Bytes Format Units Label Explanations
1- 3 A3 --- Ref Origin of redshifts (1) 5- 6 I2 h RAh Right ascension (J2000) 8- 9 I2 min RAm Right ascension (J2000) 11- 15 F5.2 s RAs Right ascension (J2000) 17 A1 --- DE- Declination sign (J2000) 18- 19 I2 deg DEd Declination (J2000) 21- 22 I2 arcmin DEm Declination (J2000) 24- 27 F4.1 arcsec DEs Declination (J2000) 29- 35 F7.5 --- z Weighted mean redshift (2) 37- 39 I3 km/s e_z ? Weighted uncertainty on redshift (2) 41- 44 F4.1 mag Bmag ? POSS II BJ magnitude (3) 46- 50 F5.1 mag BMAG ? Absolute B magnitude (4) 52- 56 F5.3 Mpc rho ? Projected distance to sight line (5)
Note (1): Only in table1: T98: Redshifts from Tripp et al., 1998, in preparation S92: Redshifts from Schneider et al., 1992AJ....103.1047S L96: Redshifts from Le Brun et al., 1996A&A...306..691L B98: Redshifts from Bowen et al. 1998MNRAS.297..239B Note (2): Weighted mean and weighted uncertainty based on redshifts measured with 2-3 templates (see Sect. 2.3). For redshifts from the literature, uncertainties are listed when provided in the original papers. All redshifts are heliocentric. Note (3): For a few objects, no magnitude is available from the POSS II database. In most cases, this indicates that the object is too faint to be detected in the POSS II survey. However, in some cases this may be due to misclassification in the POSS II database or close proximity to a bright star. Note (4): Absolute magnitude calculated using interstellar extinction corrections based on E(B-V) from Lockman & Savage, 1995, Cat. J/ApJS/97/1 and the K-correction from Peebles, 1993, Principles of Physical Cosmology (Princeton: Princeton Univ. Press), 331. K=2.5log(1+z). Note (5): Impact parameter (i.e., projected distance to sight line). The QSO coordinates (J2000) are for H1821+643 (table1.dat), RA=18 21 57.2, DE=+64 20 36 for PG 1116+215 (table2.dat), RA=11 19 08.7, DE=+21 19 18
Byte-by-byte Description of file: table4.dat table5.dat
Bytes Format Units Label Explanations
1- 7 F7.2 0.1nm Lambda Vacuum heliocentric wavelength of the line centroid 8 A1 --- n_Lambda [c] Note on Lambda (1) 10- 13 I4 0.1pm EW ? Observed equivalent width measured as described in Tripp et al., 1996ApJS..102..239T 15- 16 I2 0.1pm e_EW ? rms uncertainty on EW 17- 18 A2 --- n_EW [a e] Note on EW (1) (3) 19- 22 I4 0.1pm EWi ? For strongly blended lines, individual equivalent widths derived from profile parameters measured with VPFIT 25- 39 A15 --- Line Line identification (2) 40 A1 --- n_Line [abd] Note on Line (3) (1) 42- 48 F7.5 --- zabs ? Redshift measured with VPFIT from the G140L spectrum 50- 52 I3 km/s HV ? Heliocentric line velocity for lines due to the Galactic ISM
Note (1): the note means the following: c: Contaminated by geocoronal O I emission a: Strongly blended line Note (2): A colon indicates that the line is a probable detection but requires confirmation Note (3): the note means the following: b: This ISM line may be blended with an extragalactic H I Lyα line (see text sect. 3.1.1), which could cause this ISM line to have a more positive velocity than the other ISM lines. e: The Milky Way lines of Si II 1260.42Å and Si IV 1393.76, 1402.77Å contain substructure implying the detection of a high-velocity cloud at vISM∼200km/s. This cloud was not detected in the wideband H I 21 cm observations of Lockman & Savage, 1995, Cat. J/ApJS/97/1 d: The identification of this line is ambiguous; this could be Si III 1206.5 associated with the O VI absorber at zabs=0.22503. However, for reasons noted in the text (sect. 3.1.2, see also Savage et al., 1998AJ....115..436S), we believe the absorption is dominated by H I Lyα.
History: From ApJ electronic version
(End) James Marcout, Patricia Bauer [CDS] 20-Jan-2000
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

catalogue service