2011A&A...529A..49A

Query : 2011A&A...529A..49A

2011A&A...529A..49A - Astronomy and Astrophysics, volume 529A, 49-49 (2011/5-1)

HESS J1943+213: a candidate extreme BL Lacertae object.

ABRAMOWSKI A., ACERO F., AHARONIAN F., AKHPERJANIAN A.G., ANTON G., BALZER A., BARNACKA A., BARRES DE ALMEIDA U., BAZER-BACHI A.R., BECHERINI Y., BECKER J., BEHERA B., BERNLOEHR K., BOCHOW A., BOISSON C., BOLMONT J., BORDAS P., BORREL V., BRUCKER J., BRUN F., BRUN P., BULIK T., BUESCHING I., CARRIGAN S., CASANOVA S., CERRUTI M., CHADWICK P.M., CHARBONNIER A., CHAVES R.C.G., CHEESEBROUGH A., CHOUNET L.-M., CLAPSON A.C., COIGNET G., COLOM P., CONRAD J., DALTON M., DANIEL M.K., DAVIDS I.D., DEGRANGE B., DEIL C., DICKINSON H.J., DJANNATI-ATAIE A., DOMAINKO W., DRURY L.O'C., DUBOIS F., DUBUS G., DYKS J., DYRDA M., EGBERTS K., EGER P., ESPIGAT P., FALLON L., FARNIER C., FEGAN S., FEINSTEIN F., FERNANDES M.V., FIASSON A., FONTAINE G., FOERSTER A., FUESSLING M., GALLANT Y.A., GAST H., GERARD L., GERBIG D., GIEBELS B., GLICENSTEIN J.F., GLUECK B., GORET P., GOERING D., HAEFFNER S., HAGUE J.D., HAMPF D., HAUSER M., HEINZ S., HEINZELMANN G., HENRI G., HERMANN G., HINTON J.A., HOFFMANN A., HOFMANN W., HOFVERBERG P., HOLLER M., HORNS D., JACHOLKOWSKA A., DE JAGER O.C., JAHN C., JAMROZY M., JUNG I., KASTENDIECK M.A., KATARZYNSKI K., KATZ U., KAUFMANN S., KEOGH D., KHANGULYAN D., KHELIFI B., KLOCHKOV D., KLUZNIAK W., KNEISKE T., KOMIN N., KOSACK K., KOSSAKOWSKI R., LAFFON H., LAMANNA G., LENNARZ D., LOHSE T., LOPATIN A., LU C.-C., MARANDON V., MARCOWITH A., MASBOU J., MAURIN D., MAXTED N., McCOMB T.J.L., MEDINA M.C., MEHAULT J., NGUYEN N., MODERSKI R., MOULIN E., NAUMANN C.L., NAUMANN-GODO M., DE NAUROIS M., NEDBAL D., NEKRASSOV D., NICHOLAS B., NIEMIEC J., NOLAN S.J., OHM S., OLIVE J.-F., DE ONA WILHELMI E., OPITZ B., OSTROWSKI M., PANTER M., PAZ ARRIBAS M., PEDALETTI G., PELLETIER G., PETRUCCI P.-O., PITA S., PUEHLHOFER G., PUNCH M., QUIRRENBACH A., RAUE M., RAYNER S.M., REIMER A., REIMER O., RENAUD M., DE LOS REYES R., RIEGER F., RIPKEN J., ROB L., ROSIER-LEES S., ROWELL G., RUDAK B., RULTEN C.B., RUPPEL J., RYDE F., SAHAKIAN V., SANTANGELO A., SCHLICKEISER R., SCHOECK F.M., SCHOENWALD A., SCHULZ A., SCHWANKE U., SCHWARZBURG S., SCHWEMMER S., SHALCHI A., SIKORA M., SKILTON J.L., SOL H., SPENGLER G., STAWARZ L., STEENKAMP R., STEGMANN C., STINZING F., STYCZ K., SUSHCH I., SZOSTEK A., TAVERNET J.-P., TERRIER R., TIBOLLA O., TLUCZYKONT M., VALERIUS K., VAN ELDIK C., VASILEIADIS G., VENTER C., VIALLE J.P., VIANA A., VINCENT P., VIVIER M., VOELK H.J., VOLPE F., VOROBIOV S., VORSTER M., WAGNER S.J., WARD M., WIERZCHOLSKA A., ZAJCZYK A., ZDZIARSKI A.A., ZECH A., ZECHLIN H.-S., BURNETT T.H., HILL A.B. (The HESS Collaboration)

Abstract (from CDS):

The H.E.S.S. Cherenkov telescope array has been surveying the Galactic plane for new VHE (>100GeV) gamma-ray sources. We report on a newly detected point-like source, HESS J1943+213. This source coincides with an unidentified hard X-ray source IGR J19443+2117, which was proposed to have radio and infrared counterparts. We combine new H.E.S.S., Fermi/LAT and Nancay Radio Telescope observations with pre-existing non-simultaneous multi-wavelength observations of IGR J19443+2117 and discuss the likely source associations as well as the interpretation as an active galactic nucleus, a gamma-ray binary or a pulsar wind nebula. HESS J1943+213 is detected at the significance level of 7.9σ (post-trials) at RA(J2000)=19:43:55±1stat±1sys, Dec(J2000)=+21:18:8±17stat±20"sys. The source has a soft spectrum with photon index Γ=3.1±0.3stat±0.2sys and a flux above 470GeV of (1.3±0.2stat±0.3sys)x10–12cm–2s–1. There is no Fermi/LAT counterpart down to a flux limit of 6x10–9cm–2s–1 in the 0.1-100GeV energy range (95% confidence upper limit calculated for an assumed power-law model with a photon index Γ=2.0). The data from radio to VHE gamma-rays do not show any significant variability. The lack of a massive stellar counterpart disfavors the binary hypothesis, while the soft VHE spectrum would be very unusual in case of a pulsar wind nebula. In addition, the distance estimates for Galactic counterparts places them outside of the Milky Way. All available observations favor an interpretation as an extreme, high-frequency peaked BL Lac object with a redshift z>0.14. This would be the first time a blazar is detected serendipitously from ground-based VHE observations, and the first VHE AGN detected in the Galactic Plane.

Abstract Copyright: ∼

Journal keyword(s): galaxies: active - BL Lacertae objects: individual: IGR J19443+2117 - gamma rays: general

Simbad objects: 22

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Number of rows : 22
N Identifier Otype ICRS (J2000)
RA 		ICRS (J2000)
DEC 		Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2024 		#notes
1 QSO B0237-2322 QSO 02 40 08.1743783856 -23 09 15.729012036   16.78 16.63     ~ 506 0
2 LS I +61 303 HXB 02 40 31.6644419688 +61 13 45.593918580 11.27 11.61 10.75 10.19 9.55 B0Ve 853 2
3 NAME Per B AGN 04 37 04.37535450 +29 40 13.8179631   21.7       ~ 516 2
4 M 1 SNR 05 34 30.9 +22 00 53           ~ 6201 1
5 V* CM Tau Psr 05 34 31.9474694616 +22 00 52.153698024           ~ 5267 0
6 QSO B0548-322 BLL 05 50 40.5705144672 -32 16 16.484718648   16.07 15.5     ~ 409 1
7 HD 259440 HXB 06 32 59.2566076656 +05 48 01.160755848 9.17 9.63 9.15     B0pe 221 0
8 3C 196 Sy1 08 13 36.0561170112 +48 13 02.644966020   18.36 17.79     ~ 553 2
9 NAME Vela XYZ Rad 08 34.0 -45 50           ~ 1232 2
10 CPD-63 2495 HXB 13 02 47.6544015048 -63 50 08.626970292 10.34 10.72 9.98 10.03   O9.5Ve 793 0
11 QSO B1426+428 BLL 14 28 32.6090008440 +42 40 21.048123396   16.95 16.45 14.4   ~ 520 2
12 UGC 9799 Sy2 15 16 44.4893939136 +07 01 17.825410740   15.19 14.17     ~ 447 3
13 QSO B1553+113 BLL 15 55 43.0440048528 +11 11 24.365649948 14.91 14.72 14.57 13.99   ~ 572 1
14 PSR J1617-5055 Psr 16 17 29.35 -50 55 12.8           ~ 119 1
15 AJG 44 Psr 16 17 33.000 -51 02 00.00           ~ 512 3
16 AX J1640.7-4632 BL? 16 40 43.2 -46 31 48           ~ 158 2
17 7C 165211.80+395026.00 BLL 16 53 52.21668403 +39 45 36.6088754 14.09 14.15 13.29 8.26   ~ 2170 2
18 V* V479 Sct HXB 18 26 15.0561548880 -14 50 54.247274304 12.02 12.23 11.27 11.04   ON6V((f))z 573 2
19 AX J1838.0-0655 BL? 18 38 03.13 -06 55 33.4           ~ 78 2
20 PSR J1838-0655 Psr 18 38 03.13 -06 55 33.4           ~ 100 1
21 2MASS J19435624+2118233 Bla 19 43 56.244 +21 18 23.38           ~ 89 3
22 QSO B2344+514 BLL 23 47 04.8372110928 +51 42 17.877513168     15.50 10.7   ~ 464 0

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