Abstract
view Abstract Citations (21) References (26) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS A Radio-quiet Galaxy at Redshift Z = 3.409 Turnshek, D. A. ; Macchetto, F. ; Bencke, M. V. ; Hazard, C. ; Sparks, W. B. ; McMahon, R. G. Abstract We report the discovery of an unresolved radio-quiet object with redshift Z_em_ = 3.409 and visual magnitude v~ 24.3 +/- 0.5. The object was identified during an imaging search for Lyα emission near the redshift of a Z_abs_ = 3.390 damped Lyα absorption-line system which appears in the spectrum of the Z_em_ = 4.11 QSO 0000-2619. For H_0_ = 50 km s^-1^ Mpc^-1^ and q_0_ = 0.5, we find that the bulk of the object's Lyα and continuum emission comes from an unresolved region less than 9 kpc (FWHM ~ 1.2"), and its absolute magnitude in the rest- frame ultraviolet near Lyα is ~- 21.2. A long-slit CCD spectrum at 500 km s^-1^ resolution shows that it has kinematically unresolved Lyα emission with a rest equivalent width in the range ~10-20 A. The object's properties are therefore consistent with those of a galaxy or a burst of star formation in a galaxy. Although a number of high- redshift objects have been identified as radio galaxies, these objects are clearly active, having QSO-like luminosities in the rest-frame optical and radio. This new object would be the highest redshift radio- quiet galaxy known. The object is observed to be ~135 kpc (19") in projection from the sight line to the QSO. Previously unidentified weak absorption lines due to low- and high-ionization metals are possibly present in the QSO spectrum at Z_abs_ = 3.409 (i.e., at a redshift consistent with the emission-line redshift). If present, they would indicate the existence of an extended, gaseous region associated with the optical object. The presence of metals in the extended gas would suggest that it has been enriched by star formation. However, if this absorption system proves not to be real, then this places an upper limit on the size/covering factor of any extended absorbing region surrounding the galaxy. No emission at the redshift of the damped Lyα absorber is detected. The damped absorber has neutral hydrogen column density N(H I) ~ 3 x 10^21^ cm^-2^ and it exhibits strong metal-line transitions due to low and high-ionization species. The damped Lyα absorbers may be the progenitors of present-day galactic H I disks. Since the velocity separation of the damped absorber and the proposed new galaxy is ~1300 km s^-1^, the observations indicate that these two high-redshift objects reside in the same cluster. Publication: The Astrophysical Journal Pub Date: November 1991 DOI: 10.1086/170689 Bibcode: 1991ApJ...382...26T Keywords: Galactic Evolution; Quasars; Red Shift; Absorption Spectra; Emission Spectra; Luminosity; Lyman Alpha Radiation; Spectral Line Width; Star Formation; Astrophysics; COSMOLOGY; GALAXIES: EVOLUTION; GALAXIES: FORMATION; GALAXIES: REDSHIFTS; QUASARS full text sources ADS | data products SIMBAD (8) NED (3)
Sign-in/Register to access full text options 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a callDisclaimer: All third-party content on this website/platform is and will remain the property of their respective owners and is provided on "as is" basis without any warranties, express or implied. Use of third-party content does not indicate any affiliation, sponsorship with or endorsement by them. Any references to third-party content is to identify the corresponding services and shall be considered fair use under The CopyrightLaw.
