Abstract
Aims. Previous observations with the HESS telescope array revealed the existence of extended very-high-energy (VHE; E > 100 GeV) γ-ray emission, HESS J1023-575, coincident with the young stellar cluster Westerlund 2. At the time of discovery, the origin of the observed emission was not unambiguously identified, and follow-up observations have been performed to further investigate the nature of this γ-ray source. Methods. The Carina region towards the open cluster Westerlund 2 has been re-observed, increasing the total exposure to 45.9 h. The combined dataset includes 33 h of new data and now permits a search for energy-dependent morphology and detailed spectroscopy. Results. A new, hard spectrum VHE γ-ray source, HESS J1026-582, was discovered with a statistical significance of 7σ. It is positionally coincident with the Fermi LAT pulsar PSR J1028-5819. The positional coincidence and radio/γ-ray characteristics of the LAT pulsar favors a scenario where the TeV emission originates from a pulsar wind nebula. The nature of HESS J1023-575 is discussed in light of the deep HESS observations and recent multi-wavelength discoveries, including the Fermi LAT pulsar PSR J1022-5746 and giant molecular clouds in the region. Despite the improved VHE dataset, a clear identification of the object responsible for the VHE emission from HESS J1023-575 is not yet possible, and contribution from the nearby high-energy pulsar and/or the open cluster remains a possibility.
| Original language | English (US) |
|---|---|
| Article number | A46 |
| Journal | Astronomy and Astrophysics |
| Volume | 525 |
| Issue number | 17 |
| State | Published - Jan 1 2011 |
Keywords
- gamma rays: stars
- HII regions
Fingerprint Dive into the research topics of 'Revisiting the Westerlund 2 field with the HESS telescope array'. Together they form a unique fingerprint.
Cite this
- APA
- Standard
- Harvard
- Vancouver
- Author
- BIBTEX
- RIS
Revisiting the Westerlund 2 field with the HESS telescope array. / Abramowski, A.; Acero, F.; Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Barnacka, A.; Barres De Almeida, U.; Bazer-Bachi, A. R.; Becherini, Y.; Becker, J.; Behera, B.; Bernlöhr, K.; Bochow, A.; Boisson, C.; Bolmont, J.; Bordas, P.; Borrel, V.; Brucker, J.; Brun, F.; Brun, P.; Bulik, T.; Büsching, I.; Boutelier, T.; Casanova, S.; Cerruti, M.; Chadwick, P. M.; Charbonnier, A.; Chaves, R. C G; Cheesebrough, A.; Conrad, J.; Chounet, L. M.; Clapson, A. C.; Coignet, G.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; Dickinson, H. J.; Djannati-Ataï, A.; Domainko, W.; Drury, L. O.; 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.; Förster, A.; Fontaine, G.; Füßling, M.; Gabici, S.; Gallant, Y. A.; Gérard, L.; Gerbig, D.; Giebels, B.; Glicenstein, J. F.; Glück, B.; Goret, P.; Göring, D.; Hague, J. D.; Hampf, D.; Hauser, M.; Heinz, S.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hinton, J. A.; Hoffmann, A.; Hofmann, W.; Hofverberg, P.; Holleran, M.; Hoppe, S.; Horns, D.; Jacholkowska, A.; De Jager, O. C.; Jahn, C.; Jung, I.; Katarzyński, K.; Katz, U.; Kaufmann, S.; Kerschhaggl, M.; Khangulyan, D.; Khélifi, B.; Keogh, D.; Klochkov, D.; Kluźniak, W.; Kneiske, T.; Komin, Nu; Kosack, K.; Kossakowski, R.; Lamanna, G.; Lenain, J. P.; Lennarz, D.; Lohse, T.; Lu, C. C.; Marandon, V.; Marcowith, A.; Masbou, J.; Maurin, D.; McComb, T. J L; Medina, M. C.; Méhault, J.; Moderski, R.; Moulin, E.; Naumann-Godo, M.; De Naurois, M.; Nedbal, D.; Nekrassov, D.; Nguyen, N.; Nicholas, B.; Niemiec, J.; Nolan, S. J.; Ohm, S.; Olive, J. F.; De Oña Wilhelmi, E.; Opitz, B.; Orford, K. J.; Ostrowski, M.; Panter, M.; Paz Arribas, M.; Pedaletti, G.; Pelletier, G.; Petrucci, P. O.; Pita, S.; Pühlhofer, 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.; Schöck, F. M.; Schönwald, A.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Shalchi, A.; Sushch, I.; Sikora, M.; Skilton, J. L.; Sol, H.; Spengler, G.; Stawarz, L.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Szostek, A.; Tam, P. H.; 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.; Völk, H. J.; Volpe, F.; Vorobiov, S.; Wagner, S. J.; Ward, M.; Zdziarski, A. A.; Zech, A.; Zechlin, H. S.; Fukui, Y.; Furukawa, N.; Ohama, A.; Sano, H.; Dawson, J.; Kawamura, A.
In: Astronomy and Astrophysics, Vol. 525, No. 17, A46, 01.01.2011.Research output: Contribution to journal › Article › peer-review
}
TY - JOUR
T1 - Revisiting the Westerlund 2 field with the HESS telescope array
AU - Abramowski, A.
AU - Acero, F.
AU - Aharonian, F.
AU - Akhperjanian, A. G.
AU - Anton, G.
AU - Barnacka, A.
AU - Barres De Almeida, U.
AU - Bazer-Bachi, A. R.
AU - Becherini, Y.
AU - Becker, J.
AU - Behera, B.
AU - Bernlöhr, K.
AU - Bochow, A.
AU - Boisson, C.
AU - Bolmont, J.
AU - Bordas, P.
AU - Borrel, V.
AU - Brucker, J.
AU - Brun, F.
AU - Brun, P.
AU - Bulik, T.
AU - Büsching, I.
AU - Boutelier, T.
AU - Casanova, S.
AU - Cerruti, M.
AU - Chadwick, P. M.
AU - Charbonnier, A.
AU - Chaves, R. C G
AU - Cheesebrough, A.
AU - Conrad, J.
AU - Chounet, L. M.
AU - Clapson, A. C.
AU - Coignet, G.
AU - Dalton, M.
AU - Daniel, M. K.
AU - Davids, I. D.
AU - Degrange, B.
AU - Deil, C.
AU - Dickinson, H. J.
AU - Djannati-Ataï, A.
AU - Domainko, W.
AU - Drury, L. O.
AU - Dubois, F.
AU - Dubus, G.
AU - Dyks, J.
AU - Dyrda, M.
AU - Egberts, K.
AU - Eger, P.
AU - Espigat, P.
AU - Fallon, L.
AU - Farnier, C.
AU - Fegan, S.
AU - Feinstein, F.
AU - Fernandes, M. V.
AU - Fiasson, A.
AU - Förster, A.
AU - Fontaine, G.
AU - Füßling, M.
AU - Gabici, S.
AU - Gallant, Y. A.
AU - Gérard, L.
AU - Gerbig, D.
AU - Giebels, B.
AU - Glicenstein, J. F.
AU - Glück, B.
AU - Goret, P.
AU - Göring, D.
AU - Hague, J. D.
AU - Hampf, D.
AU - Hauser, M.
AU - Heinz, S.
AU - Heinzelmann, G.
AU - Henri, G.
AU - Hermann, G.
AU - Hinton, J. A.
AU - Hoffmann, A.
AU - Hofmann, W.
AU - Hofverberg, P.
AU - Holleran, M.
AU - Hoppe, S.
AU - Horns, D.
AU - Jacholkowska, A.
AU - De Jager, O. C.
AU - Jahn, C.
AU - Jung, I.
AU - Katarzyński, K.
AU - Katz, U.
AU - Kaufmann, S.
AU - Kerschhaggl, M.
AU - Khangulyan, D.
AU - Khélifi, B.
AU - Keogh, D.
AU - Klochkov, D.
AU - Kluźniak, W.
AU - Kneiske, T.
AU - Komin, Nu
AU - Kosack, K.
AU - Kossakowski, R.
AU - Lamanna, G.
AU - Lenain, J. P.
AU - Lennarz, D.
AU - Lohse, T.
AU - Lu, C. C.
AU - Marandon, V.
AU - Marcowith, A.
AU - Masbou, J.
AU - Maurin, D.
AU - McComb, T. J L
AU - Medina, M. C.
AU - Méhault, J.
AU - Moderski, R.
AU - Moulin, E.
AU - Naumann-Godo, M.
AU - De Naurois, M.
AU - Nedbal, D.
AU - Nekrassov, D.
AU - Nguyen, N.
AU - Nicholas, B.
AU - Niemiec, J.
AU - Nolan, S. J.
AU - Ohm, S.
AU - Olive, J. F.
AU - De Oña Wilhelmi, E.
AU - Opitz, B.
AU - Orford, K. J.
AU - Ostrowski, M.
AU - Panter, M.
AU - Paz Arribas, M.
AU - Pedaletti, G.
AU - Pelletier, G.
AU - Petrucci, P. O.
AU - Pita, S.
AU - Pühlhofer, G.
AU - Punch, M.
AU - Quirrenbach, A.
AU - Raue, M.
AU - Rayner, S. M.
AU - Reimer, A.
AU - Reimer, O.
AU - Renaud, M.
AU - De Los Reyes, R.
AU - Rieger, F.
AU - Ripken, J.
AU - Rob, L.
AU - Rosier-Lees, S.
AU - Rowell, G.
AU - Rudak, B.
AU - Rulten, C. B.
AU - Ruppel, J.
AU - Ryde, F.
AU - Sahakian, V.
AU - Santangelo, A.
AU - Schlickeiser, R.
AU - Schöck, F. M.
AU - Schönwald, A.
AU - Schwanke, U.
AU - Schwarzburg, S.
AU - Schwemmer, S.
AU - Shalchi, A.
AU - Sushch, I.
AU - Sikora, M.
AU - Skilton, J. L.
AU - Sol, H.
AU - Spengler, G.
AU - Stawarz, L.
AU - Steenkamp, R.
AU - Stegmann, C.
AU - Stinzing, F.
AU - Szostek, A.
AU - Tam, P. H.
AU - Tavernet, J. P.
AU - Terrier, R.
AU - Tibolla, O.
AU - Tluczykont, M.
AU - Valerius, K.
AU - Van Eldik, C.
AU - Vasileiadis, G.
AU - Venter, C.
AU - Vialle, J. P.
AU - Viana, A.
AU - Vincent, P.
AU - Vivier, M.
AU - Völk, H. J.
AU - Volpe, F.
AU - Vorobiov, S.
AU - Wagner, S. J.
AU - Ward, M.
AU - Zdziarski, A. A.
AU - Zech, A.
AU - Zechlin, H. S.
AU - Fukui, Y.
AU - Furukawa, N.
AU - Ohama, A.
AU - Sano, H.
AU - Dawson, J.
AU - Kawamura, A.
PY - 2011/1/1
Y1 - 2011/1/1
N2 - Aims. Previous observations with the HESS telescope array revealed the existence of extended very-high-energy (VHE; E > 100 GeV) γ-ray emission, HESS J1023-575, coincident with the young stellar cluster Westerlund 2. At the time of discovery, the origin of the observed emission was not unambiguously identified, and follow-up observations have been performed to further investigate the nature of this γ-ray source. Methods. The Carina region towards the open cluster Westerlund 2 has been re-observed, increasing the total exposure to 45.9 h. The combined dataset includes 33 h of new data and now permits a search for energy-dependent morphology and detailed spectroscopy. Results. A new, hard spectrum VHE γ-ray source, HESS J1026-582, was discovered with a statistical significance of 7σ. It is positionally coincident with the Fermi LAT pulsar PSR J1028-5819. The positional coincidence and radio/γ-ray characteristics of the LAT pulsar favors a scenario where the TeV emission originates from a pulsar wind nebula. The nature of HESS J1023-575 is discussed in light of the deep HESS observations and recent multi-wavelength discoveries, including the Fermi LAT pulsar PSR J1022-5746 and giant molecular clouds in the region. Despite the improved VHE dataset, a clear identification of the object responsible for the VHE emission from HESS J1023-575 is not yet possible, and contribution from the nearby high-energy pulsar and/or the open cluster remains a possibility.
AB - Aims. Previous observations with the HESS telescope array revealed the existence of extended very-high-energy (VHE; E > 100 GeV) γ-ray emission, HESS J1023-575, coincident with the young stellar cluster Westerlund 2. At the time of discovery, the origin of the observed emission was not unambiguously identified, and follow-up observations have been performed to further investigate the nature of this γ-ray source. Methods. The Carina region towards the open cluster Westerlund 2 has been re-observed, increasing the total exposure to 45.9 h. The combined dataset includes 33 h of new data and now permits a search for energy-dependent morphology and detailed spectroscopy. Results. A new, hard spectrum VHE γ-ray source, HESS J1026-582, was discovered with a statistical significance of 7σ. It is positionally coincident with the Fermi LAT pulsar PSR J1028-5819. The positional coincidence and radio/γ-ray characteristics of the LAT pulsar favors a scenario where the TeV emission originates from a pulsar wind nebula. The nature of HESS J1023-575 is discussed in light of the deep HESS observations and recent multi-wavelength discoveries, including the Fermi LAT pulsar PSR J1022-5746 and giant molecular clouds in the region. Despite the improved VHE dataset, a clear identification of the object responsible for the VHE emission from HESS J1023-575 is not yet possible, and contribution from the nearby high-energy pulsar and/or the open cluster remains a possibility.
KW - gamma rays: stars
KW - HII regions
UR - http://www.scopus.com/inward/record.url?scp=79951490595&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=79951490595&partnerID=8YFLogxK
M3 - Article
VL - 525
JO - Astronomy and Astrophysics
JF - Astronomy and Astrophysics
SN - 0004-6361
IS - 17
M1 - A46
ER -