2024A&A...687A.219H

Query : 2024A&A...687A.219H

2024A&A...687A.219H - Astronomy and Astrophysics, volume 687A219 (2024/7-1)

H.E.S.S. observations of the 2021 periastron passage of PSR B1259-63/LS 2883.

HESS COLLABORATION, AHARONIAN F., AIT BENKHALI F., ASCHERSLEBEN J., ASHKAR H., BACKES M., BARBOSA MARTINS V., BATZOFIN R., BECHERINI Y., BERGE D., BERNLOHR K., BOTTCHER M., BOISSON C., BOLMONT J., DE BONY DE LAVERGNE M., BOROWSKA J., BOUYAHIAOUI M., BROSE R., BROWN A., BRUN F., BRUNO B., BULIK T., BURGER-SCHEIDLIN C., CAROFF S., CASANOVA S., CELIC J., CERRUTI M., CHAND T., CHANDRA S., CHEN A., CHIBUEZE J., CHIBUEZE O., COTTER G., DAMASCENE MBARUBUCYEYE J., DEVIN J., DJUVSLAND J., DMYTRIIEV A., EGBERTS K., EINECKE S., ERNENWEIN J.-P., FONTAINE G., FUNK S., GABICI S., GALLANT Y.A., GLAWION D., GLICENSTEIN J.F., GOSWAMI P., GROLLERON G., HAERER L., HESS B., HOFMANN W., HOLCH T.L., HOLLER M., HUANG Z., JAMROZY M., JANKOWSKY F., JOSHI V., JUNG-RICHARDT I., KASAI E., KATARZYNSKI K., KHANGULYAN D., KHATOON R., KHELIFI B., KLUZNIAK W., KOMIN N., KOSACK K., KOSTUNIN D., KUNDU A., LANG R.G., LE STUM S., LEITL F., LEMIERE A., LEMOINE-GOUMARD M., LENAIN J.-P., LEUSCHNER F., MACKEY J., MALYSHEV D., MARTI-DEVESA G., MARX R., MEHTA A., MEINTJES P.J., MITCHELL A., MODERSKI R., MOHRMANN L., MONTANARI A., MOULIN E., MURACH T., DE NAUROIS M., NIEMIEC J., OHM S., DE ONA WILHELMI E., OSTROWSKI M., PANNY S., PANTER M., PARSONS R.D., PENSEC U., PERON G., PROKHOROV D.A., PUHLHOFER G., PUNCH M., QUIRRENBACH A., REGEARD M., REIMER A., REIMER O., REIS I., REN H., RIEGER F., RUDAK B., RUIZ-VELASCO E., SAHAKIAN V., SALZMANN H., SANTANGELO A., SASAKI M., SCHAFER J., SCHUSSLER F., SCHUTTE H.M., SHAPOPI J.N.S., SPENCER S., STAWARZ L., STEENKAMP R., STEINMASSL S., STEPPA C., STREIL K., SUSHCH I., TAKAHASHI T., TANAKA T., TAYLOR A.M., TERRIER R., THORPE-MORGAN C., TLUCZYKONT M., UNBEHAUN T., VAN ELDIK C., VAN SOELEN B., VECCHI M., VENTER C., VINK J., WACH T., WAGNER S.J., WERNER F., WIERZCHOLSKA A., ZACHARIAS M., ZDZIARSKI A.A., ZECH A. and ZYWUCKA N.

Abstract (from CDS):

PSR B1259-63/LS 2883 is a gamma-ray binary system that hosts a pulsar in an eccentric orbit, with a 3.4 yr period, around an O9.5Ve star (LS 2883). At orbital phases close to periastron passages, the system radiates bright and variable non-thermal emission, for which the temporal and spectral properties of this emission are, for now, poorly understood. In this regard, very high-energy (VHE) emission is especially useful to study and constrain radiation processes and particle acceleration in the system. We report on an extensive VHE observation campaign conducted with the High Energy Stereoscopic System, comprised of approximately 100 h of data taken over five months, from t_p - 24 days to t_p + 127 days around the system's 2021 periastron passage (where t_p is the time of periastron). We also present the timing and spectral analyses of the source. The VHE light curve in 2021 is consistent overall with the stacked light curve of all previous observations. Within the light curve, we report a VHE maximum at times coincident with the third X-ray peak first detected in the 2021 X-ray light curve. In the light curve - although sparsely sampled in this time period - we see no VHE enhancement during the second disc crossing. In addition, we see no correspondence to the 2021 GeV flare in the VHE light curve. The VHE spectrum obtained from the analysis of the 2021 dataset is best described by a power law of spectral index Γ = 2.65 ± 0.04_stat ± 0.04_sys, a value consistent with the spectral index obtained from the analysis of data collected with H.E.S.S. during the previous observations of the source. We report spectral variability with a difference of ΔΓ = 0.56 ± 0.18_stat ± 0.10_sys at 95% confidence intervals, between sub-periods of the 2021 dataset. We also detail our investigation into X-ray/TeV and GeV/TeV flux correlations in the 2021 periastron passage. We find a linear correlation between contemporaneous flux values of X-ray and TeV datasets, detected mainly after t_p + 25 days, suggesting a change in the available energy for non-thermal radiation processes. We detect no significant correlation between GeV and TeV flux points, within the uncertainties of the measurements, from ∼t_p - 23 days to ∼t_p + 126 days. This suggests that the GeV and TeV emission originate from different electron populations.

Abstract Copyright: © The Authors 2024

Journal keyword(s): radiation mechanisms: non-thermal - binaries: general - pulsars: individual: PSR B1259-63/LS 2883

Simbad objects: 5

Full paper

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Number of rows : 5

N	Identifier	Otype	ICRS (J2000) RA	ICRS (J2000) DEC	Mag U	Mag B	Mag V	Mag R	Mag I	Sp type	#ref 1850 - 2026	#notes
1	LS I +61 303	HXB	02 40 31.6644419688	+61 13 45.593918580	11.27	11.61	10.75	10.19	9.55	B0Ve	903	2
2	CPD-63 2495	HXB	13 02 47.6544015048	-63 50 08.626970292	10.34	10.72	9.98	10.03		O9.5Ve	852	0
3	PSR J1301-6305	Psr	13 02 47.9992676	-63 10 48.001099						~	139	2
4	V* V479 Sct	HXB	18 26 15.0561548880	-14 50 54.247274304	12.02	12.23	11.27	11.04		ON6V((f))z	613	2
5	[MT91] 213	Psr	20 32 13.1247390384	+41 27 24.346666440	13.12	13.08	11.266			B0Vp	334	0

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