Analysis of SN 2021hiz in UGC7513 (IC3322A)

The light curve was acquired with the following equipment:
-        Meade APO 115 with focal reducer
-        ASI1600 mm cool
-        ZWO new R, G, B filter setEach point consisted in 4 x 5mn exposures thru each filter.

The SN2021hiz  was imaged for light curve during the nights of 6, 7, 9, 11, 16, 17, 18, 19, 20, 22, 29 & 30 of April and 1, 2, 3, 5, 6, 9, 12, 14, 15 & 31 of May 2021.

The color calibration of the filters was performed in PI using APASS catalog with stars in the field of view. In particular, the B filter was calibrated using the APASS Blue channel and the APASS B-V index.

According to our data, the B mag maximum occurred on April the 15 @ 16h GMT+2 at B mag = 13.27
At T max + 15 days, the B mag was recorded at 14.41The SN absolute magnitude of the maximum was estimated at Mmax(B) = -18.64, using the Phillips relationship (Wikipedia)  
The total reddening (due to both interstellar dust and UGC7513 dust), was estimated using the differences between B and V channels at:
-        tmax                           : where a pristine SN shows a B-V of 0.0
-        tmax + 15           : where a pristine SN shows a B-V of 1.1
In our case these two values are consistent with a B-V excess: E[B-V] = 0.03
The B extinction is computed as 2 x E[B-V] = 0.06

The corrected Bmag @ max is therefore = 13.21, which set the galaxy distance at:
75.7 M Light-Years or 23.2 M parsecs. This compare very well with available distances from scientific publications (see below).

Using the R filter, we can approximately identify the probable location of the NIR second maximum about 28 days after the primary maximum.

Some information on the photometry analysis.
The analysis was performed with PixInsight Aperture Photometry Script.The RA and DEC of the SN were input as custom object.Similarly, 2 points adjacent to the SN photometry aperture AND located on each of the SN over the background galaxy (UGC7513) were entered as additional photometric custom objects.The background level of UGC7513 was estimated as the average between these two reference points, and used for correcting the flux from the SN itself.

The color calibration of the ZWO new RGB filter set was performed for each point (for each day).  The Median Absolute Deviation of the reference stars was 0.02 mag on average.


References :


AVAILABLE MEASUREMENTS OF DISTANCES