Alert Notice 826: Supernova in M101 - SN 2023ixf in NGC 5457

May 22, 2023

AAVSO Forum threads (scroll to the bottom of a thread for latest posts):
- Time Sensitive Alerts: https://www.aavso.org/sn-2023ixf-m101
- Cataclysmic Variables: https://www.aavso.org/sn-2023ixf-m101-01

Please subscribe to these threads if you are observing this supernova so you can be updated as to its behavior and any observing campaigns on it. Join in the discussion or ask questions there!

Event: Supernova in M101 - SN 2023ixf in NGC 5457 (UMa)

Discovered by: Koichi Itagaki (Yamagata, Japan)

Discovery magnitude: 14.9 unfiltered CCD

Discovery date: 2023 May 19.7272569 UT

Coordinates (2000.0): R.A. 14 03 38.58   Decl. +54 18 42.1   (from VSX page for SN 2023ixf)
(located 227.7" east and 134.1" south of the center of M101)

Spectra: Spectroscopy indicating the object to be a Type II supernova was obtained on 2023 May 19.93316 UT with the SPRAT (SPectrograph for the Rapid Acquisition of Transients) instrument on the Liverpool Telescope by D. Perley et al.  (AstroNote 2023-119).

General observing recommendations: Please observe SN 2023ixf as it continues to evolve, with observations of all types (visual, CCD/CMOS, DSLR, spectroscopy) and multiple bands as instrumentation permits. Frequency of observation depends on the rate of decline; a minimum of one observation per night per band is recommended.

Observations reported to the AAVSO:  (selected from over 450 observations at time of Alert Notice preparation)
2023 May 18.33 UT, <20-21 clear filter (pre-discovery, D. Kennedy, reported in K. Zhang et al., AstroNote 125);
18.4286458, <20.5 ATLAS orange (pre-discovery, ATLAS, reported by M. Fulton et al., AstroNote 2023-124);
19.02292, 17.3: BVR (pre-discovery, B. Ostermeyer, reported in K. Zhang et al., AstroNote 2023-125);
19.1625, 15.5 clear filter +/-0.5 (pre-discovery, S. Limeburner, AstroNote 2023-128);
19.2555556, 16.0 USNO R2 +/-0.3 (pre-discovery, A. Filippenko, W. Zheng, and Y. Yang, magnitude cautioned, see AstroNote 2023-123);
19.3229977, 15.87 g +/-0.01 (pre-discovery, Zwicky Transient Facility, reported by D. Perley et al., AstroNote 2023-120);
19.34167, 15.3: clear filter (Kennedy);
19.7272569, 14.9 unfiltered CCD (discovery, K. Itagaki, Yamagata, Japan);
20.22742, 13.523 V +/-0.011 (R. Tomlin, Big Rock, IL);
20.24103, 13.513 B +/-0.010 (Tomlin);
20.25600, 13.404 I +/-0.016 (Tomlin);
20.45210, 13.05 V +/-0.003 (R. Fidrich, Budapest, Hungary);
20.83548, 12.293 CV +/-0.025 (M. Urbanik, Cadca, Slovak Republic);
20.85000, 12.1 (B. Bago, Piliscsaba, Hungary);
20.86319, 12.2 CV (K. Wenzel, Grossostheim, Germany);
20.91667, 12.2 (J. De Wit, Belgium);
20.93543, 12.268 V +/-0.005 (J. Vannini, Luma, Peru);
20.93966, 11.970 B +/-0.009 (Vannini);
20.95096, 12.097 V +/-0.013 (I. Sharp, Chicester, UK);
20.95172, 12.309 R +/-0.008 (A. Diepvens, Olmen-Balen, Belgium);
20.96181, 12.1 (H. Dahle, Oslo, Norway);
20.97348, 11.903 TG +/-0.052 (G. Williamson, UK);
20.98800, 12.0 (G. Poyner, Birmingham, UK);
21.00896, 12.066 R +/-0.003 (Sharp);
21.03100, 12.05 CV +/-0.005 (Poyner);
21.06058, 11.913 B +/-0.003 (Sharp);
21.14583, 11.75 (S. Harrington, Evening Shade, AR);
21.14610, 11.706 B +/-0.002 (Tomlin);
21.14912, 11.988 V +/-0.002 (Tomlin);
21.15144, 12.048 I +/-0.003 (Tomlin);
21.16528, 11.75 (L. Herrington, Ketchum, OK);
21.16667, 11.7 (Harrington);
21.20833, 12.2 (J. Barentine, Tucson, AZ);
21.37500, 11.75 (Harrington);
21.82528, 11.512 CV +/-0.038 (Urbanik);
21.82986, 11.8 (A. Kosa-Kiss, Salonta, Romania);
21.85000, 11.4 (Bago);
21.87200, 11.5 (W. Vollmann, Vienna, Austria);
21.87780, 11.7 (W. Kriebel, Schierling/Walkenstetten, Germany);
21.87900, 11.223 B +/-0.003 (O. Nickel, Mainz, Germany);
21.87984, 11.455 V +/-0.003 (Nickel);
21.87986, 11.6 CV (Wenzel);
21.88071, 11.440 R +/-0.004 (Nickel);
21.88400, 11.8 (G. Gilein, Noordwijk, Netherlands);
21.90200, 11.398 CV +/-0.005 (Poyner);
21.92014, 11.1 (P. Guzik, Niżna Łąka, Poland);
21.92708, 11.3 (P. Abel, Leicester, UK);
22.08560, 11.384 CV +/-0.007 (D. Collins, Swannanoa, NC);
22.14120, 11.327 V +/-0.024 (N. Thomas, Carefree, AZ);
22.16528, 11.5 (Zhu);
22.16667, 10.8 (Harrington);
22.18425, 11.325 V +/-0.069 (D. Crowson, O'Fallon, MO);
22.18750, 11.1 (Barentine);
22.25000, 11.4 (R. Howard, Oakland, CA);
22.88042, 11.1696 V +/-0.0066 (I. Peretto, Spagnago, Italy);
22.92014, 11.0 (E. Illes, Bakonya, Hungary);

Charts: Charts with comparison stars for SN 2023ixf may be created using the AAVSO Variable Star Plotter (VSP).

Submit observations: Please submit observations using the name SN 2023ixf.
 - Submit optical observations to the AAVSO International Database using WebObs.
 - Submit spectra to the AAVSO Spectroscopy Database (AVSpec).
 
Notes:
a. Designated SN 2023ixf when posted to the Transient Name Server and confirmed as a supernova.

b. Perley et al. (see above) report that a possible progenitor candidate is located at RA 14:03:38.51, Dec +54:18:42:10 (2000.0).

Congratulations to Koichi Itagaki on his latest discovery!

This AAVSO Alert Notice was compiled by Elizabeth O. Waagen.
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