Redshift determination of the very high energy gamma-ray extreme blazar PGC 2402248
ATel #11621; J. Becerra Gonzalez (Instituto de Astrofisica de Canarias -IAC-), R. Clavero (Isaac Newton Group of telescopes), L. Peralta de Arriba (University of Cambridge), J. A. Acosta (IAC) and R. Garcia Lopez (IAC)
on 8 May 2018; 16:31 UT
Credential Certification: Josefa Becerra Gonzalez (josefa.becerra@nasa.gov)
Subjects: Optical, TeV, VHE, AGN, Blazar
Recently, the MAGIC collaboration announced the detection of very-high-energy gamma-ray emission (VHE, E>100 GeV) from the extreme blazar PGC 2402248 (also known as 2WHSP J073326.7+515354; ATel #11548), which redshift was unknown. Its optical counterpart is located at coordinates R.A.: 7:33:26.81 h and Dec:+51:53:56.0 deg. We obtained a high-SNR spectrum with the 10.4m GTC telescope within the DDT proposal GTC2018-099, to investigate weak spectral features from a low-SNR spectrum obtained previously from the 2.5m INT telescope. The observations were carried out on 02/05/2018 with OSIRIS in longslit configuration and grism R1000B, covering the wavelength range from 3650 to 7700 A. The redshift of PGC 2402248 was measured as z=0.065, derived from the identification of several spectral features: CaII doublet, G-band, MgI and NaD.
We would like to thank the ING staff, GTC staff, the Spanish CAT and the IAC director for making these observations possible.
