Dinosaur in a Haystack: X-Ray View of the Entrails of SN 2023ixf and the Radio Afterglow of Its Interaction with the Medium Spawned by the Progenitor Star (Paper I)

Creators: A. J., Nayana¹; Margutti, Raffaella¹; Wiston, Eli¹; Chornock, Ryan¹; Campana, Sergio²; Laskar, Tanmoy^{3, 4}; Murase, Kohta^{5, 6}; Krips, Melanie⁷; Migliori, Giulia⁸; Tsuna, Daichi^{9, 10}; Alexander, Kate D.¹¹; Chandra, Poonam¹²; Bietenholz, Michael¹³; Berger, Edo¹⁴; Chevalier, Roger A.¹⁵; De Colle, Fabio¹⁶; Dessart, Luc¹⁷; Diesing, Rebecca¹⁸; Grefenstette, Brian W.⁹; Jacobson-Galán, Wynn V.^{1, 9}; Maeda, Keiichi⁶; Marcote, Benito^{19, 20}; Matthews, Daisy²¹; Milisavljevic, Dan²²; Ray, Alak K.²³; Reguitti, Andrea²; Polzin, Ava²⁴

1. University of California, Berkeley
2. INAF–Osservatorio Astronomico di Brera, Via Bianchi 46, I-23807, Merate (LC), Itay
3. University of Utah
4. Radboud University Nijmegen
5. Pennsylvania State University
6. Kyoto University
7. International Research Institute for Radio Astronomy
8. Istituto di Radioastronomia di Bologna
9. California Institute of Technology
10. University of Tokyo
11. University of Arizona
12. National Radio Astronomy Observatory
13. SARAO/Hartebeesthoek Radio Observatory, PO Box 443, Krugersdorp 1740, South Africa
14. Harvard-Smithsonian Center for Astrophysics
15. University of Virginia
16. National Autonomous University of Mexico
17. Institut d'Astrophysique de Paris
18. Institute for Advanced Study
19. Joint Institute for VLBI in Europe
20. Netherlands Institute for Radio Astronomy
21. Illinois Institute of Technology
22. Purdue University West Lafayette
23. Homi Bhabha Centre for Science Education
24. University of Chicago

Abstract

We present the results from our extensive hard-to-soft X-ray (NuSTAR, Swift-XRT, XMM-Newton, Chandra) and meter-to-millimeter-wave radio (Giant Metrewave Radio Telescope, Very Large Array, NOEMA) monitoring campaign of the very nearby (d = 6.9 Mpc) Type II supernova (SN) 2023ixf spanning ≈4–165 days post-explosion. This unprecedented data set enables inferences on the explosion's circumstellar medium (CSM) density and geometry. In particular, we find that the luminous X-ray emission is well modeled by thermal free–free radiation from the forward shock with rapidly decreasing photoelectric absorption with time. The radio spectrum is dominated by synchrotron radiation from the same shock. Similar to the X-rays, the level of free–free absorption affecting the radio spectrum rapidly decreases with time as a consequence of the shock propagation into the dense CSM. While the X-ray and the radio modeling independently support the presence of a dense medium corresponding to an effective mass-loss rate M˙≈10⁻⁴M⊙yr⁻¹ at R = (0.4–14) × 10¹⁵ cm (for v_w = 25 km s⁻¹), our study points at a complex CSM density structure with asymmetries and clumps. The inferred densities are ≈10–100 times those of typical red supergiants, indicating an extreme mass-loss phase of the progenitor in the ≈200 yr preceding core collapse, which leads to the most X-ray luminous Type II SN and the one with the most delayed emergence of radio emission. These results add to the picture of the complex mass-loss history of massive stars on the verge of collapse and demonstrate the need for panchromatic campaigns to fully map their intricate environments.

Copyright and License

Original content from this work may be used under the terms of the Creative Commons Attribution 4.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI.

Acknowledgement

This work is based on observations carried out under project No. d23ab with the IRAM NOEMA Interferometer [30 m telescope]. IRAM is supported by INSU/CNRS (France), MPG (Germany), and IGN (Spain). The National Radio Astronomy Observatory is a facility of the National Science Foundation operated under cooperative agreement by Associated Universities, Inc. We thank the staff of the GMRT that made these observations possible. The GMRT is run by the National Centre for Radio Astrophysics of the Tata Institute of Fundamental Research. This research has made use of the NuSTAR Data Analysis Software (NuSTARDAS) jointly developed by the ASI Space Science Data Center (SSDC, Italy) and the California Institute of Technology (Caltech, USA). Partially based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. This paper employs a list of Chandra data sets, obtained by the Chandra X-ray Observatory, contained in doi:10.25574/cdc.351. This research has made use of the XRT Data Analysis Software (XRTDAS) developed under the responsibility of the ASI Science Data Center (ASDC), Italy. This work made use of data supplied by the UK Swift Science Data Centre at the University of Leicester. This research has made use of data and software provided by the High Energy Astrophysics Science Archive Research Center (HEASARC), which is a service of the Astrophysics Science Division at NASA/GSFC.

This work was performed in part at the Aspen Center for Physics, which is supported by National Science Foundation grant PHY-2210452. The collaboration of D.T. and R.M. was facilitated by interactions that were funded by the Gordon and Betty Moore Foundation through grant GBMF5076. R.M. acknowledges support by the National Science Foundation under award No. AST-2221789 and AST-2224255, and by NASA under grant 80NSSC22K1587. The TReX team at UC Berkeley is partially funded by the Heising-Simons Foundation under grant 2021-3248 (PI: Margutti). The work of K.M. is partially supported by the NSF grants No. AST-2108466, No. AST-2108467, and No. AST-2308021, and KAKENHI No. 20H05852. D.T. acknowledges support by the Sherman Fairchild Postdoctoral Fellowship at the California Institute of Technology. P.C. acknowledges support from NASA through Chandra award No. DD3-24141X issued by the Chandra X-ray Center. K.M. acknowledges support from the Japan Society for the Promotion of Science (JSPS) KAKENHI grant JP24KK0070 and 24H01810. F.D.C. acknowledges support from DGAPA/PAPIIT grant IN113424. Andrea Reguitti acknowledges financial support from the GRAWITA Large Program grant (PI P. D'Avanzo) and the PRIN-INAF 2022 "Shedding light on the nature of gap transients: from the observations to the models". G.M. acknowledges financial support from the INAF mini-grant "The high-energy view of jets and transients" (Bando Ricerca Fondamentale INAF 2022). S.C. thanks Norbert Schartel for granting the first XMM-Newton observation. S.C. acknowledges support from ASI. B.M. acknowledges financial support from the State Agency for Research of the Spanish Ministry of Science and Innovation, and FEDER, UE, under grant PID2022-136828NB-C41/MICIU/AEI/10.13039/501100011033, and through the Unit of Excellence Marìa de Maeztu 2020–2023 award to the Institute of Cosmos Sciences (CEX2019- 000918-M). The European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program ('EuroFlash': grant agreement No. 101098079).

Facilities

HST - Hubble Space Telescope satellite (STIS), Swift - Swift Gamma-Ray Burst Mission (XRT and UVOT), AAVSO - American Association of Variable Star Observers International Database, CTIO:1.3m - Cerro Tololo Inter-American Observatory's 1.3 meter Telescope, CTIO:1.5m - Cerro Tololo Inter-American Observatory's 1.5 meter Telescope, CXO - Chandra X-ray Observatory satellite.

Software References

astropy (Astropy Collaboration et al. 2013, 2018).

Additional Information

The title was inspired by a news report on the rediscovery of fossilized dinosaur eggs in rural Gujarat in Indian Express 2024 October 28.

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