Swift observations of MASTER OT J120451.50+265946.6 (Type Ib SN)
ATel #6719; Raffaella Margutti (Harvard University), Peter J. Brown (Texas A&M/Mitchell Institute), Atish Kamble (Harvard University), Dan Milisavljevic (SAO), Jerod Parrent (Harvard University), Alicia M. Soderberg (Harvard University)
on 19 Nov 2014; 16:17 UT
Credential Certification: Raffaella Margutti (email@example.com)
Subjects: Ultra-Violet, X-ray, Supernovae
MASTER OT J120451.50+265946.6 (Atel #6634) has been recently classified as a Type Ib SN a few weeks after maximum light (Atel #6639, #6640, #6641). MASTER OT J120451.50+265946.6 exploded in NGC 4080 (distance of 15 Mpc, Karachentsev et al., 2013). Bright radio emission associated with this transient was reported by Kamble (Atel #6712).
A Swift-ToO was executed to observe the field of MASTER OT J120451.50+265946.6 starting on October 29th, 2014 (PI Brown). We do not find evidence for X-ray emission at the location of the SN using the data collected by the Swift XRT in the time period October 29th- November 4th. We calculate a 3 sigma upper limit of 2.1d-3 c/s in the 0.3-10 keV energy band (total exposure time of 5.2 ks). The Galactic neutral hydrogen column density in the direction of MASTER OT J120451.50+265946.6 is 1.7d20 cm-2 (Kalberla 2005). Assuming a spectral photon index ~2, we infer an absorbed flux limit of 7.3d-14 erg/s/cm2 (0.3-10 keV), corresponding to a luminosity limit of 2.1d39 erg/s at the distance of 15 Mpc. Further observations are planned.
We also report on Swift/UVOT measurements from the first observation beginning 2014-10-29 12:05:43 using the pipeline for the Swift Optical/Ultraviolet Supernova Archive (SOUSA; Brown et al. 2014, Ap&SS, 354, 89). The SN is clearly detected in the optical but not the UV. We measure v=14.9 +/- 0.1, b=16.6 +/-0.2, u=18 +/- 0.3, uvw1>18.2, uvm2>18.3, uvw2>18.5, where the uncertainties and upper limits are dominated by the host galaxy contamination.
We thank the Swift team for scheduling these ToO observations.