Possible radio and IR counterparts of the unidentified MILAGRO source MGRO J1908+06 (HESS J1908+063)

ATel #1247; Jorge A. Combi (Universidad de Jaén-UJA), Josep Martí (UJA), Pedro Luque-Escamilla (UJA), Alvaro Muñoz-Arjonilla and Juan R. Sánchez-Sutil
on 21 Oct 2007; 22:31 UT
Credential Certification: Jorge Ariel Combi (jcombi@ujaen.es)

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Within the error box of the new VHE source HESS J1908+063 (astro-ph/07102418), which coincides with the recently reported MILAGRO unidentified source MGRO J1908+06, we have found one weak radio source in the 1.4 GHz NVSS maps and the variable star V* V347 Aql. The radio source, named NVSS J190803+061822, is located at an estimated J2000.0 ICRS position of RA=19h08m03.73s (+/-0.43s), DEC=+06d18'22.4" (+/-10.5") (1-sigma uncertainties), with a 20 cm flux density of 9.1 (+/- 1.9) mJy and may have a faint near IR counterpart in the 2MASS images (see the NVSS and Ks-band 2MASS plots, where the circle and rectangle represent the 1-sigma uncertainties, respectively). Inside the HESS 1-sigma error circle, it is also located the variable M6 star V* V347 Aql, with coordinates J2000.0 ICRS position of RA=19h08m01.3s, DEC=+06d18'27. The source has optical magnitude B=11.5 in the USNO-B1.0 catalog and infrared magnitudes J= 1.809, H= 0.302, Ks= 0.250 (2MASS 19080112+0618272) in the 2MASS catalog. There is no catalogued X-ray source inside any 1-sigma radius position error circle. We suggest that both sources could be competing counterparts to the unidentified MILAGRO source MGRO J1908+06. Further multiwavelength observations are encouraged to unveil the nature of this VHE source.