The redshift of the optical transient associated with GRB 010222

Saurabh Jha, Michael A. Pahre, Peter M. Garnavich, Michael L. Calkins, Roy E. Kilgard, Thomas Matheson, Jonathan C. Mcdowell, John B. Roll, Krzysztof Z. Stanek

Research output: Contribution to journalArticlepeer-review

42 Scopus citations


The gamma-ray burst (GRB) 010222 is the brightest GRB detected to date by the BeppoSAX satellite. Prompt identification of the associated optical transient (OT) allowed for spectroscopy with the Tillinghast 1.5 m telescope at F. L. Whipple Observatory while the source was still relatively bright (R ≃ 18.6 mag), within 5 hr of the burst. The OT shows a blue continuum with many superposed absorption features corresponding to metal lines at z = 1.477, 1.157, and possibly also 0.928. The redshift of GRB 010222 is therefore unambiguously placed at z ≥ 1.477. The high number of Mg II absorbers and especially the large equivalent widths of the Mg II, Mg I, and Fe II absorption lines in the z = 1.477 system further argue either for a very small impact parameter or that the z = 1.477 system is the GRB host galaxy itself. The spectral index of the OT is relatively steep, Fv α ν-0.89±0.03, and this cannot be caused by dust with a standard Galactic extinction law in the z = 1.477 absorption system. This spectroscopic identification of the redshift of GRB 010222 shows that prompt and wellcoordinated follow-up of bright GRBs can be successful even with telescopes of modest aperture.

Original languageEnglish (US)
Pages (from-to)L155-L158
JournalAstrophysical Journal
Issue number2 PART 2
StatePublished - Jun 20 2001

All Science Journal Classification (ASJC) codes

  • Astronomy and Astrophysics
  • Space and Planetary Science


  • Galaxies: ISM
  • Galaxies: distances and redshifts
  • Gamma rays: bursts
  • Ultraviolet: galaxies


Dive into the research topics of 'The redshift of the optical transient associated with GRB 010222'. Together they form a unique fingerprint.

Cite this