Analysis of the archival HST images of PTF11kly in M101
ATel #3582; Weidong Li (UCB), Peter Nugent (LBL/UCB), Josh Bloom (UCB), and Alex Filippenko (LBL/UCB) report on behalf of a large collaboration:
on 25 Aug 2011; 03:51 UT
Credential Certification: Weidong Li (weidong@astron.berkeley.edu)
Subjects: Optical, Supernovae, Transient
We have analyzed the discovery images of PTF11kly, a probable very young Type Ia
supernova, reported by Nugent et al. (ATEL #3581) and performed astrometric solutions to
match archival images (Program ID: 9490) taken by the Advanced Camera for Surveys (ACS)
with the Hubble Space Telescope (HST) in November 2002. We were able to locate the
supernova position on the ACS images to an uncertainty of 58 mas (1 sigma). A figure on
the site of PTF11kly in the ACS/F435W, F555W, and F814W filters is shown at http://astro.berkeley.edu/~weidong/m101sn.gif
Each section is 5" x 5" with North is up and East to the left. The circles have a radius
of 348 mas which is 6 times the 1 sigma
error radius of our astrometric solution. No object is visible at the nominal position of
the SN. We note, however, the presence of
two sources (marked as "1" and "2") within roughly the 2 x 1 sigma uncertainty of our
solution. These two sources appear rather red:
they are clearly detected in the F814W image, only marginally detected in F555W, and not
detected in F435W. High-resolution imaging should improve our astrometric solution, and
help investigate whether these two red sources are related to PTF11kly. Further analysis
of the photometry and upper limits of the images is in progress.
