DRAFT
2023-05-27 00:20:20
Type: Object/s-Data/Analysis
Bibcode: 2023TNSAN.147....1M
Identification of a red supergiant candidate progenitor in the HST and IRAC images
Authors: Divakara Mayya
Keywords: Supernova
Abstract:
I here report a candidate for the progenitor of SN2023ixf. The archival HST and other multi-band images in the NASA Extragalactic Database (NED) were used to search for the progenitor at the reported position of SN2023ixf. We find the candidate progenitor in the F814W (I) image at a magnitude of 24.41 +/- 0.06, with no detection in the HST F435W (B) and F555W (V) bands. The progenitor is also seen in the Spitzer IRAC 3.6 and 4.5 bands, with I-3.6 color = 7.42 +/- 1.40 and 3.6 - 4.5 = 0.97 +/- 0.10. At the adopted distance modulus of 29.21 (Riess et al. 2016 ApJ 826, 56), the inferred absolute magnitude M_I = -4.80, and colors (in VEGA system) are consistent with the progenitor as a red supergiant surrounded by vast amount of circumstellar material, most likely due to high mass-loss rate of the progenitor in its final phase before the explosion (e.g. Yang et al. 2018 A&A 616, A175).

The HST images from a1 Field of View were downloaded from the Hubble Legacy Archive, and astrometrically registered using more than 100 point sources in the 2MASS and SDSS catalogues. IRAC images did not require any astrometric correction. Magnitudes are obtained in circular apertures centered at RA=14:03:38.561 Dec=+54:18:42.05, using a radius of 0.2 arcsec for the HST images and 2.5 arcsec for the IRAC images, subtracting a sky flux from an annulus just outside the photometric apertures. Magnitudes are obtained in the VEGA system using the zeropoints listed in Lomelí-Núñez et al. (2022; MNRAS 509, 180) for the a1 field for the HST images. Appropriate aperture corrections are applied to the IRAC fluxes, which were also expressed in the Vega magnitude system using the Vega fluxes in Jy in these bands. A 3-sigma upper limits are calculated for the F435W and F555W filters to determine lower limits on the optical colors. A distance modulus of 29.21 (Riess et al. 2016 ApJ 826, 56) is adopted to obtain the absolute magnitude. No correction for interstellar reddening is carried out. However, the Galactic interstellar extinction towards M101 is low (Av=0.023 mag; NED). Conversion to the AB system gives an absolute magnitude of [3.6]=-9.45 and [3.6]-[4.5]=0.49, which are in excellent agreement with the MIR properties of Red supergiants in the LMC as reported by Yang et al. (2018; A&A 616, A175).

The resulting magnitudes and colors for the progenitor candidate of SN2023ixf are:
           mVega  Err  Mvega
HST/F435W >27.53
HST/F555W >27.12
HST/F814W  24.41 0.06  -4.80
IRAC_3.6   16.98 1.40  -12.23
IRAC_4.5   16.01 1.20  -13.20

B-I > 3.12
V-I > 2.11
I - 3.6 = 7.42 +/- 1.40
3.6 - 4.5 = 0.97 +/- 0.10

 

Show current TNS values
Catalog Name Reported RA Reported DEC Reported Obj-Type Reported Redshift Host Name Host Redshift Remarks TNS RA TNS DEC TNS Obj-Type TNS Redshift
TNS 2023ixf 14:03:38.562 +54:18:41.94 SN IIn 0.0008 M101 14:03:38.562 +54:18:41.94 SN II 0.0008
File Comments
M101_SN2023ixf_stamps.png Images show the candidate progenitor enclosed with an 1 arcsec diameter aperture in the filters indicated in the figure legend. The last image shows an RGB image formed using the HST F814W, F656N (Halpha) and F435W as red, green and blue components, respectively. The F656N (Halpha) image helps to infer the absence of any ionized gas in the displayed region. The red color of the candidate progenitor can be easily inferred in the color image.

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