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Swift/XRT follow-up observation of IGR J12131+0700 (not NGC 4180)

ATEL # 1310; R. Landi, A. Malizia, N. Masetti (INAF/IASF Bologna), A. De Rosa, S. Gianni' (INAF/IASF Rome), A.J. Dean, M. Molina (Univ. Southampton), N. Gehrels, J. Tueller (NASA/GSFC), P. Giommi (ASDC), J.A. Kennea (PSU)
on 28 Nov 2007; 16:24 UT
Password Certification: Raffaella Landi (

Subjects: X-ray, Gamma Ray, AGN

IGR J12131+0700 (not NGC 4180)
The third IBIS survey contains a source at RA(J2000) = 183.291 and Dec(J2000) = +7.009, initially associated to the galaxy NGC 4180, which has been recently classified as a possible Seyfert 2 galaxy (Masetti et al. 2007, Atel 1033). Swift/XRT has now observed this sky region for 4.6 ksec and detected within the IBIS uncertainty (5.1 arcmin), two sources at:

1) RA(J2000) = 12h 12m 49.62s, Dec(J2000) = +06d 59s 44.6s (5.1 arcsec uncertainty, 5.3 sigma)
2) RA(J2000) = 12h 12m 56.60s, Dec(J2000) = +07d 03s 06.7s (6 arcsec uncertainty, 3.6 sigma)

Object N.1 coincides with the QSO SDSS J121249.84+065945.4 (also NVSS J121249+065950) at z = 0.2095 and has a 2-10 keV flux of 1.5 x 10-13 erg cm-2 s-1 (Gamma = 1.8). The other source has no obvious association in Simbad, NED or HEASARC and is characterized by a 2-10 keV flux of 0.8 x 10-13 erg cm-2 s-1 (Gamma = 1.8).
No excess emission is detected at the position of NGC 4180 with an upper limit to the 2-10 keV flux of 0.2 x 10-13 erg cm-2 s-1. NGC 4180 may still be the counterpart of the IBIS source, if it is heavily absorbed, i.e. it is a Compton thick AGN.
Due to the complexity of this field, we suggest to rename the IBIS source as IGR J12131+0700.

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R. E. Rutledge , Editor
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