Longtime Monitoring of TeV Radio Galaxies with HAWC
Abstract We present the monitoring of the TeV-emitting radio galaxies M87, NGC 1275, 3C 264, and IC 310 with the High-Altitude Water Cherenkov Observatory (HAWC) over a period of approximately 7.5 yr. The analysis includes light curves at daily, weekly, and monthly timescales for the four sources. We report the detection of gamma-ray emission from M87 with a significance exceeding 5 σ , providing the integrated TeV spectrum from the longest temporal coverage to date. The source is well described as a point-like source modeled by a power-law spectrum with spectral index Γ = 2.53 ± 0.29 and a flux of (7.09 ± 1.24) × 10 −13 cm −2 s −1 TeV −1 at 1 TeV. The maximum energy of the detected emission in M87, at 1 σ confidence level, reaches 26.5 TeV. HAWC’s observation of M87 reveals a low flux spectrum for the longest observation to date of this radio galaxy. 3C 264 is marginally detected with a significance slightly below 4 σ , while NGC 1275 and IC 310 are not detected. The weekly light curves show an increased number of fluxes above 2 σ for M87 starting in 2019 and for 3C 264 starting in 2018, which can be interpreted as the moments at which these sources start to exhibit an enhanced steady TeV emission. Cumulative significance analysis reveals quantitative evidence for long-term variability. M87 shows enhanced emission from 2019, while 3C 264 exhibits increased activity from 2018, resembling variable sources like Markarian 421 rather than steady sources like the Crab. This supports the importance of monitoring radio galaxies to identify periods of higher activity and flares, enabling further multimessenger studies.
Authors
- H. Zhou (ORCID: https://orcid.org/0000-0003-0513-3841)
- Niccolò Di Lalla (ORCID: https://orcid.org/0000-0002-7574-1298)
- Rishi Babu (ORCID: https://orcid.org/0000-0002-5529-6780)
- E. Belmont‐Moreno (ORCID: https://orcid.org/0000-0003-3207-105X)
- S. Coutinõ de León (ORCID: https://orcid.org/0000-0002-7747-754X)
- J. A. Morales-Soto (ORCID: https://orcid.org/0000-0001-9361-0147)
- A. Lara (ORCID: https://orcid.org/0000-0001-6336-5291)
- Enrique Varela (ORCID: https://orcid.org/0000-0003-0715-7513)
- P. Desiati (ORCID: https://orcid.org/0000-0001-9768-1858)
- E. Moreno (ORCID: https://orcid.org/0000-0002-1114-2640)
- T. Capistrán (ORCID: https://orcid.org/0000-0003-2158-2292)
- J. Cotzomi (ORCID: https://orcid.org/0000-0002-1132-871X)
- Y. Pérez Araujo (ORCID: https://orcid.org/0000-0002-8774-8147)
- R. Torres-Escobedo (ORCID: https://orcid.org/0000-0002-7102-3352)
- P. Miranda-Romagnoli (ORCID: https://orcid.org/0000-0002-8390-9011)
- E. De la Fuente (ORCID: https://orcid.org/0000-0001-9643-4134)
- U. Cotti (ORCID: https://orcid.org/0000-0002-7607-9582)
- I. Herzog (ORCID: https://orcid.org/0000-0001-5169-723X)
- A. Nayerhoda
- J. C. Díaz–Vélez (ORCID: https://orcid.org/0000-0002-0087-0693)
- Dezhi Huang (ORCID: https://orcid.org/0000-0002-5447-1786)
- S. Kaufmann
- K. Malone (ORCID: https://orcid.org/0000-0001-8088-400X)
- S. Casanova (ORCID: https://orcid.org/0000-0002-6144-9122)
- L. Villaseñor
- L. Nellen (ORCID: https://orcid.org/0000-0003-1059-8731)
- J. A. Goodman (ORCID: https://orcid.org/0000-0002-9790-1299)
- Shaoqing Yu (ORCID: https://orcid.org/0000-0003-2208-4535)
- O. Tibolla (ORCID: https://orcid.org/0000-0002-9074-0584)
- José Serna-Franco (ORCID: https://orcid.org/0009-0007-7409-4061)
- J. Martínez-Castro (ORCID: https://orcid.org/0000-0002-2824-3544)
- I. J. Watson
- Y. Son (ORCID: https://orcid.org/0000-0002-7214-8480)
- H. y. Wu (ORCID: https://orcid.org/0000-0001-5928-195X)
- I. Torres (ORCID: https://orcid.org/0000-0002-1689-3945)
- G. Luis-Raya (ORCID: https://orcid.org/0000-0003-2810-4867)
- Kirsten Tollefson (ORCID: https://orcid.org/0000-0001-9725-1479)
- E. G. Pérez‐Pérez (ORCID: https://orcid.org/0000-0001-5998-4938)
- H. León Vargas (ORCID: https://orcid.org/0000-0001-5516-4975)
- A. Sandoval (ORCID: https://orcid.org/0000-0001-6079-2722)
- D. Kieda (ORCID: https://orcid.org/0000-0003-4785-0101)
- C. Espinoza (ORCID: https://orcid.org/0000-0001-7074-1726)
- K. S. Caballero‐Mora (ORCID: https://orcid.org/0000-0002-4042-3855)
- R. W. Springer (ORCID: https://orcid.org/0000-0002-1492-0380)
- Chang Dong Rho (ORCID: https://orcid.org/0000-0002-6524-9769)
- F. Garfias (ORCID: https://orcid.org/0000-0003-1122-4168)
- D. Rosa‐González (ORCID: https://orcid.org/0000-0003-1327-0838)
- P. Bangale (ORCID: https://orcid.org/0000-0002-3886-3739)
- A. L. Longinotti (ORCID: https://orcid.org/0000-0001-8825-3624)
- F. Hueyotl‐Zahuantitla (ORCID: https://orcid.org/0000-0002-5527-7141)
- A. Iriarte (ORCID: https://orcid.org/0000-0001-5811-5167)
- M. A. DuVernois (ORCID: https://orcid.org/0000-0002-2987-9691)
- A. Carramiñana (ORCID: https://orcid.org/0000-0002-8553-3302)
- Alfonso Muñoz (ORCID: https://orcid.org/0000-0003-3347-6518)
- T. Ergin (ORCID: https://orcid.org/0000-0003-2423-4656)
- E. Ponce (ORCID: https://orcid.org/0000-0001-8960-6495)
- J. P. Harding (ORCID: https://orcid.org/0000-0001-9844-2648)
- C. de León (ORCID: https://orcid.org/0000-0002-8528-9573)
- M. Najafi (ORCID: https://orcid.org/0000-0002-7576-4799)
- M. Mostafá (ORCID: https://orcid.org/0000-0002-7675-4656)
- J. A. García-González (ORCID: https://orcid.org/0000-0002-4188-5584)
- M. M. González (ORCID: https://orcid.org/0000-0002-5209-5641)
- M. Osorio (ORCID: https://orcid.org/0009-0009-2481-6921)
- K. Engel (ORCID: https://orcid.org/0000-0001-5737-1820)
- Davide Depaoli (ORCID: https://orcid.org/0000-0002-2672-4141)
- H. A. Ayala Solares (ORCID: https://orcid.org/0000-0002-2084-5049)
- J. Lee
- S. Fraija (ORCID: https://orcid.org/0009-0008-8311-6290)
- José A. González (ORCID: https://orcid.org/0000-0002-2753-696X)
- O. Martı́nez (ORCID: https://orcid.org/0000-0001-9052-856X)
- John A. Matthews (ORCID: https://orcid.org/0000-0002-2610-863X)
- X. Wang (ORCID: https://orcid.org/0000-0001-6798-353X)
- M. Schneider (ORCID: https://orcid.org/0000-0001-8644-4734)
- N. Fraija (ORCID: https://orcid.org/0000-0002-0173-6453)
- A. Rodriguez Parra
- D. Avila Rojas (ORCID: https://orcid.org/0000-0002-4020-4142)
- R. Diaz Hernandez
- F. Carreón
- J. C. Arteaga‐Velázquez (ORCID: https://orcid.org/0009-0005-5590-8563)
- M. Roth
- N. Omodei (ORCID: https://orcid.org/0000-0002-5448-7577)
- C. Álvarez (ORCID: https://orcid.org/0000-0003-0815-7953)
- S. Groetsch
- R. Alfaro Molina (ORCID: https://orcid.org/0000-0002-4713-7069)
- Z. Wang
- H. Salazar (ORCID: https://orcid.org/0009-0009-3426-1616)
- A. Bernal (ORCID: https://orcid.org/0009-0006-6671-5166)
- E. Anita-Rangel
Institutions
- Universidad Autónoma del Estado de Hidalgo (MX)
- Michigan Technological University (US)
- University of Seoul (KR)
- Pennsylvania State University (US)
- Los Alamos National Laboratory (US)
- University of Wisconsin–Madison (US)
- University of New Mexico (US)
- Universidad Michoacana de San Nicolás de Hidalgo (MX)
- Shanghai Jiao Tong University (CN)
- Universidad de Guadalajara (MX)
- Missouri University of Science and Technology (US)
- University of Utah (US)
- National Institute of Astrophysics, Optics and Electronics (MX)
- Universidad Politécnica de Pachuca (MX)
- Institute of Nuclear Physics, Polish Academy of Sciences (PL)
- Energy Center of Wisconsin (US)
- Universidad Autónoma de Chiapas (MX)
- Max Planck Institute for Nuclear Physics (DE)
- Institute of Natural Science (KP)
- University of Turin (IT)
- Instituto Politécnico Nacional (MX)
- University of Maryland, College Park (US)
- Benemérita Universidad Autónoma de Puebla (MX)
- Temple University (US)
- Sungkyunkwan University (KR)
- Michigan State University (US)
- Universidad Nacional Autónoma de México (MX)
- Stanford University (US)
- Tecnológico de Monterrey (MX)
Publication Details
- Journal
- The Astrophysical Journal
- Published
- 2025-11-25
- DOI
- https://doi.org/10.3847/1538-4357/ae1009
- Citations
- 2
- Primary Topic
- Astrophysics and Cosmic Phenomena
- Type
- article
- Field-Weighted Citation Impact
- 3.74