STATION 04 · MULTI-MESSENGER WIRE DOSSIER Supernova / Optical CONFIRMED

SN 2023ixf

“Closest Core-Collapse Supernova in a Decade in Pinwheel Galaxy (M101)”

Zwicky Transient Facility (ZTF) / Itagaki • Trigger: 2023-05-19 17:27:15 UTC

ASTROPHYSICAL LOCALIZATION & TELEMETRY

FRAME: ICRS / J2000

Sky Coordinates 14h 03m 38.56s +54° 18' 56.4" (210.91067°, 54.31567°)

Cosmological Redshift z = 0.0008 Luminosity Dist: 21 Million ly (6.4 Mpc)

Constellation / Field Ursa Major (Messier 101) Host Field Environment

Detection Significance Peak Magnitude V = 10.8 (Visible in Binoculars) Multi-detector confidence

sn type

Type II (Core-collapse hydrogen-rich)

peak apparent mag

10.8 mag (Visual)

absolute mag

-18.3 mag

progenitor

Red Supergiant (~12–15 M☉) identified in archival HST images

circumstellar mass

~0.01 M☉ ejected in final ~1–2 years prior to core collapse

shock velocity

~10,000 km/s

01 Scientific Overview & Source Physics

SN 2023ixf was a brilliant Type II supernova discovered in the spiral arms of Messier 101 (The Pinwheel Galaxy) at a distance of only 21 million light-years. Early "flash spectroscopy" during the first 24 hours revealed intense, narrow emission lines indicating the shock breakout was plowing into dense circumstellar material ejected by the red supergiant progenitor just months before detonation.

02 Multi-Messenger Follow-Up Campaign Matrix

Observatory / Instrument	Spectral Regime	Observational Detection & Counterpart Findings
Keck Observatory (LRIS)	Flash Spectroscopy	High-ionization emission lines (C IV, N IV, He II) disappearing within 3 days as wind swept up.
Swift UVOT / XRT	UV & Soft X-ray	Early UV plateau followed by shock interaction soft X-ray emission.
VLA & NOEMA	Radio / Millimeter	Prompt millimeter detection probing circumstellar density profile.