TY  - EJOUR
AU  - Adams, C. B.
AU  - Archer, A.
AU  - Bangale, P.
AU  - Bartkoske, J. T.
AU  - Benbow, W.
AU  - Buckley, J. H.
AU  - Chen, Y.
AU  - Christiansen, J. L.
AU  - Chromey, A. J.
AU  - Duerr, A.
AU  - Errando, M.
AU  - Godoy, M. Escobar
AU  - Falcone, A.
AU  - Feldman, S.
AU  - Feng, Q.
AU  - Fortson, L.
AU  - Furniss, A.
AU  - Hanlon, W.
AU  - Hervet, O.
AU  - Hinrichs, C. E.
AU  - Holder, J.
AU  - Humensky, T. B.
AU  - Jin, W.
AU  - Johnson, M. N.
AU  - Kaaret, P.
AU  - Kertzman, M.
AU  - Kherlakian, M.
AU  - Kieda, D.
AU  - Kleiner, T. K.
AU  - Korzoun, N.
AU  - Krennrich, F.
AU  - Kumar, S.
AU  - Kundu, S.
AU  - Lang, M. J.
AU  - Lundy, M.
AU  - Maier, G.
AU  - Millard, M. J.
AU  - Millis, J.
AU  - Mooney, C. L.
AU  - Moriarty, P.
AU  - Mukherjee, R.
AU  - Ning, W.
AU  - Ong, R. A.
AU  - Pandey, A.
AU  - Pohl, M.
AU  - Pueschel, E.
AU  - Quinn, J.
AU  - Rabinowitz, P. L.
AU  - Ragan, K.
AU  - Reynolds, P. T.
AU  - Ribeiro, D.
AU  - Rizk, L.
AU  - Roache, E.
AU  - Sadeh, I.
AU  - Saha, L.
AU  - Sembroski, G. H.
AU  - Shang, R.
AU  - Splettstoesser, M.
AU  - Tak, D.
AU  - Talluri, A. K.
AU  - Tucci, J. V.
AU  - Valverde, J.
AU  - Williams, D. A.
AU  - Wong, S. L.
AU  - Woo, J.
AU  - Kwong, J.
AU  - Mori, K.
AU  - Hailey, C. J.
AU  - Safi-Harb, S.
AU  - Zhang, S.
AU  - Tsuji, N.
AU  - Manconi, S.
AU  - Donato, F.
AU  - Di Mauro, M.
TI  - Multiwavelength observation of a candidate pulsar halo LHAASO J0621+3755 and the first X-ray detection of PSR J0622+3749
IS  - arXiv:2504.02185
M1  - PUBDB-2025-04856
M1  - arXiv:2504.02185
PY  - 2025
N1  - Accepted for publication in ApJ. 28 pages, 19 figures
AB  - Pulsar halos are regions around middle-aged pulsars extending out to tens of parsecs. The large extent of the halos and well-defined central cosmic-ray accelerators make this new class of Galactic sources an ideal laboratory for studying cosmic-ray transport. LHAASO J0621+3755 is a candidate pulsar halo associated with the middle-aged gamma-ray pulsar PSR J0622+3749. We observed LHAASO J0621+3755 with VERITAS and XMM-Newton in the TeV and X-ray bands, respectively. For this work, we developed a novel background estimation technique for imaging atmospheric Cherenkov telescope observations of such extended sources. No halo emission was detected with VERITAS (0.3-10 TeV) or XMM-Newton (2-7 keV) within 1 degree and 10 arcmin around PSR J0622+3749, respectively. Combined with the LHAASO-KM2A and Fermi-LAT data, VERITAS flux upper limits establish a spectral break at  1-10 TeV, a unique feature compared with Geminga, the most studied pulsar halo. We model the gamma-ray spectrum and LHAASO-KM2A surface brightness as inverse Compton emission and find suppressed diffusion around the pulsar, similar to Geminga. A smaller diffusion suppression zone and harder electron injection spectrum than Geminga are necessary to reproduce the spectral cutoff. A magnetic field
KW  - High Energy Astrophysical Phenomena (astro-ph.HE) (Other)
KW  - Instrumentation and Methods for Astrophysics (astro-ph.IM) (Other)
KW  - FOS: Physical sciences (Other)
LB  - PUB:(DE-HGF)25
DO  - DOI:10.3204/PUBDB-2025-04856
UR  - https://bib-pubdb1.desy.de/record/640717
ER  -