2005A&A...430..865A

Query : 2005A&A...430..865A

2005A&A...430..865A - Astronomy and Astrophysics, volume 430865-875 (2005/2-2)

H.E.S.S. observations of PKS 2155-304.

AHARONIAN F., AKHPERJANIAN A.G., AYE K.-M., BAZER-BACHI A.R., BEILICKE M., BENBOW W., BERGE D., BERGHAUS P., BERNLOEHR K., BOLZ O., BOISSON C., BORGMEIER C., BREITLING F., BROWN A.M., BUSSONS GORDO J., CHADWICK P.M., CHITNIS V.R., CHOUNET L.-M., CORNILS R., COSTAMANTE L., DEGRANGE B., DJANNATI-ATAIE A., DRURY L.O'C., ERGIN T., ESPIGAT P., FEINSTEIN F., FLEURY P., FONTAINE G., FUNK S., GALLANT Y.A., GIEBELS B., GILLESSEN S., GORET P., GUY J., HADJICHRISTIDIS C., HAUSER M., HEINZELMANN G., HENRI G., HERMANN G., HINTON J.A., HOFMANN W., HOLLERAN M., HORNS D., DE JAGER O.C., JUNG I., KHELIFI B., KOMIN N., KONOPELKO A., LATHAM I.J., LE GALLOU R., LEMOINE M., LEMIERE A., LEROY N., LOHSE T., MARCOWITH A., MASTERSON C., McCOMB T.J.L., DE NAUROIS M., NOLAN S.J., NOUTSOS A., ORFORD K.J., OSBORNE J.L., OUCHRIF M., PANTER M., PELLETIER G., PITA S., POHL M., PUEHLHOFER G., PUNCH M., RAUBENHEIMER B.C., RAUE M., RAUX J., RAYNER S.M., REDONDO I., REIMER A., REIMER O., RIPKEN J., RIVOAL M., ROB L., ROLLAND L., ROWELL G., SAHAKIAN V., SAUGE L., SCHLENKER S., SCHLICKEISER R., SCHUSTER C., SCHWANKE U., SIEWERT M., SOL H., STEENKAMP R., STEGMANN C., TAVERNET J.-P., THEORET C.G., TLUCZYKONT M., VAN DER WALT D.J., VASILEIADIS G., VINCENT P., VISSER B., VOELK H.J. and WAGNER S.J.

Abstract (from CDS):

The high-frequency peaked BL Lac PKS 2155-304 at redshift z=0.117 has been detected with high significance (∼45σ) at energies greater than 160GeV, using the H.E.S.S. stereoscopic array of imaging air-Cherenkov telescopes in Namibia. A strong signal is found in each of the data sets corresponding to the dark periods of July and October, 2002, and June-September, 2003. The observed flux of VHE gamma rays shows variability on time scales of months, days, and hours. The monthly-averaged integral flux above 300 GeV varies between 10% and 60% of the flux observed from the Crab Nebula. Energy spectra are measured for these individual periods of data taking and are characterized by a steep power law with a time-averaged photon index of Γ=3.32±0.06. An improved χ² per degree of freedom is found when either a power law with an exponential cutoff energy or a broken power law are fit to the time-averaged energy spectrum. However, the significance of the improvement is marginal (∼2σ). The suggested presence of features in the energy spectrum may be intrinsic to the emission from the blazar, or an indication of absorption of TeV gamma rays by the extragalactic infrared background light.

Abstract Copyright: ∼

Journal keyword(s): galaxies: active - galaxies: BL Lacertae objects: individual: PKS 2155-304 - gamma rays: observations

Simbad objects: 7

Full paper

View the references in ADS

Number of rows : 7

N	Identifier	Otype	ICRS (J2000) RA	ICRS (J2000) DEC	Mag U	Mag B	Mag V	Mag R	Sp type	#ref 1850 - 2026	#notes
1	M 1	SNR	05 34 31.8	+22 01 03					~	6516	1
2	V* CM Tau	Psr	05 34 31.9474694616	+22 00 52.153698024					~	5476	0
3	Z 184-50	BLL	11 04 27.3140835504	+38 12 31.798495872		13.50	12.90	8.31	~	2841	1
4	RX J1428.5+4240	BLL	14 28 32.6090008440	+42 40 21.048123396		16.95	16.45	14.4	~	549	1
5	Z 225-7	BLL	16 53 52.21668403	+39 45 36.6088754	14.09	14.15	13.29	8.26	~	2304	2
6	QSO B1959+650	BLL	19 59 59.8520303688	+65 08 54.652536492			12.8	11.21	~	699	2
7	PKS J2158-3013	BLL	21 58 52.0652249880	-30 13 32.118447792		13.36	13.09	12.62	~	1829	1

To bookmark this query, right click on this link: simbad:objects in 2005A&A...430..865A and select 'bookmark this link' or equivalent in the popup menu