Fermi large area telescope study of cosmic rays and the interstellar medium in nearby molecular clouds

M. Ackermann, M. Ajello, A. Allafort, L. Baldini, J. Ballet, G. Barbiellini, D. Bastieri, K. Bechtol, R. Bellazzini, B. Berenji, R. D. Blandford, E. D. Bloom, E. Bonamente, A. W. Borgland, E. Bottacini, T. J. Brandt, J. Bregeon, M. Brigida, P. Bruel, R. Buehler & 144 others G. Busetto, S. Buson, G. A. Caliandro, R. A. Cameron, P. A. Caraveo, J. M. Casandjian, C. Cecchi, E. Charles, A. Chekhtman, J. Chiang, S. Ciprini, R. Claus, J. Cohen-Tanugi, J. Conrad, F. D'Ammando, A. De Angelis, F. De Palma, C. D. Dermer, S. W. Digel, E. Do Couto E Silva, P. S. Drell, A. Drlica-Wagner, L. Falletti, C. Favuzzi, S. J. Fegan, E. C. Ferrara, W. B. Focke, Y. Fukazawa, Y. Fukui, S. Funk, P. Fusco, F. Gargano, D. Gasparrini, S. Germani, N. Giglietto, F. Giordano, M. Giroletti, T. Glanzman, G. Godfrey, I. A. Grenier, M. H. Grondin, J. E. Grove, S. Guiriec, D. Hadasch, Y. Hanabata, A. K. Harding, K. Hayashi, D. Horan, X. Hou, R. E. Hughes, R. Itoh, M. S. Jackson, G. Jóhannesson, A. S. Johnson, T. Kamae, H. Katagiri, Jun Kataoka, J. Knödlseder, M. Kuss, J. Lande, S. Larsson, S. H. Lee, M. Lemoine-Goumard, F. Longo, F. Loparco, M. N. Lovellette, P. Lubrano, P. Martin, M. N. Mazziotta, J. E. McEnery, J. Mehault, P. F. Michelson, W. Mitthumsiri, T. Mizuno, A. A. Moiseev, C. Monte, M. E. Monzani, A. Morselli, I. V. Moskalenko, S. Murgia, M. Naumann-Godo, R. Nemmen, S. Nishino, J. P. Norris, E. Nuss, M. Ohno, T. Ohsugi, A. Okumura, N. Omodei, E. Orlando, J. F. Ormes, M. Ozaki, D. Paneque, J. H. Panetta, D. Parent, M. Pesce-Rollins, M. Pierbattista, F. Piron, G. Pivato, T. A. Porter, S. Rainò, R. Rando, M. Razzano, A. Reimer, O. Reimer, C. Romoli, M. Roth, T. Sada, H. F W Sadrozinski, D. A. Sanchez, C. Sbarra, C. Sgrò, E. J. Siskind, G. Spandre, P. Spinelli, A. W. Strong, D. J. Suson, H. Takahashi, T. Takahashi, T. Tanaka, J. G. Thayer, J. B. Thayer, D. J. Thompson, L. Tibaldo, O. Tibolla, M. Tinivella, D. F. Torres, G. Tosti, A. Tramacere, E. Troja, Y. Uchiyama, T. Uehara, T. L. Usher, J. Vandenbroucke, V. Vasileiou, G. Vianello, V. Vitale, A. P. Waite, P. Wang, B. L. Winer, K. S. Wood, H. Yamamoto, Z. Yang, S. Zimmer

    Research output: Contribution to journalArticle

    35 Citations (Scopus)

    Abstract

    We report an analysis of the interstellar γ-ray emission from the Chamaeleon, R Coronae Australis (R CrA), and Cepheus and Polaris flare regions with the Fermi Large Area Telescope. They are among the nearest molecular cloud complexes, within 300pc from the solar system. The γ-ray emission produced by interactions of cosmic rays (CRs) and interstellar gas in those molecular clouds is useful to study the CR densities and distributions of molecular gas close to the solar system. The obtained γ-ray emissivities above 250MeV are (5.9 ± 0.1stat +0.9 -1.0sys) × 10-27photonss-1sr-1 H-atom-1, (10.2 ± 0.4stat +1.2 -1.7sys) × 10 -27photonss-1sr-1 H-atom-1, and (9.1 ± 0.3stat +1.5 -0.6sys) × 10 -27photonss-1sr-1 H-atom-1 for the Chamaeleon, R CrA, and Cepheus and Polaris flare regions, respectively. Whereas the energy dependences of the emissivities agree well with that predicted from direct CR observations at the Earth, the measured emissivities from 250MeV to 10 GeV indicate a variation of the CR density by 20% in the neighborhood of the solar system, even if we consider systematic uncertainties. The molecular mass calibrating ratio, X CO = N(H2)/W CO, is found to be (0.96 ± 0.06stat +0.15 -0.12sys) × 1020 H2-moleculecm-2 (Kkms -1)-1, (0.99 ± 0.08stat +0.18 -0.10sys) × 1020 H2-moleculecm -2 (Kkms-1)-1, and (0.63 ± 0.02 stat +0.09 -0.07sys) × 1020 H2-moleculecm-2 (Kkms-1)-1 for the Chamaeleon, R CrA, and Cepheus and Polaris flare regions, respectively, suggesting a variation of X CO in the vicinity of the solar system. From the obtained values of X CO, the masses of molecular gas traced by W CO in the Chamaeleon, R CrA, and Cepheus and Polaris flare regions are estimated to be 5 × 103 M, 103 M, and 3.3 × 104 M ,respectively. A comparable amount of gas not traced well by standard H I and CO surveys is found in the regions investigated.

    Original languageEnglish
    Article number22
    JournalAstrophysical Journal
    Volume755
    Issue number1
    DOIs
    Publication statusPublished - 2012 Aug 10

    Fingerprint

    molecular clouds
    solar system
    cosmic ray
    coronas
    flares
    cosmic rays
    emissivity
    corona
    telescopes
    rays
    molecular gases
    gas
    atoms
    interstellar gas
    calibrating
    gases
    interactions
    energy

    Keywords

    • cosmic rays
    • gamma rays: ISM

    ASJC Scopus subject areas

    • Space and Planetary Science
    • Astronomy and Astrophysics

    Cite this

    Ackermann, M., Ajello, M., Allafort, A., Baldini, L., Ballet, J., Barbiellini, G., ... Zimmer, S. (2012). Fermi large area telescope study of cosmic rays and the interstellar medium in nearby molecular clouds. Astrophysical Journal, 755(1), [22]. https://doi.org/10.1088/0004-637X/755/1/22

    Fermi large area telescope study of cosmic rays and the interstellar medium in nearby molecular clouds. / Ackermann, M.; Ajello, M.; Allafort, A.; Baldini, L.; Ballet, J.; Barbiellini, G.; Bastieri, D.; Bechtol, K.; Bellazzini, R.; Berenji, B.; Blandford, R. D.; Bloom, E. D.; Bonamente, E.; Borgland, A. W.; Bottacini, E.; Brandt, T. J.; Bregeon, J.; Brigida, M.; Bruel, P.; Buehler, R.; Busetto, G.; Buson, S.; Caliandro, G. A.; Cameron, R. A.; Caraveo, P. A.; Casandjian, J. M.; Cecchi, C.; Charles, E.; Chekhtman, A.; Chiang, J.; Ciprini, S.; Claus, R.; Cohen-Tanugi, J.; Conrad, J.; D'Ammando, F.; De Angelis, A.; De Palma, F.; Dermer, C. D.; Digel, S. W.; Do Couto E Silva, E.; Drell, P. S.; Drlica-Wagner, A.; Falletti, L.; Favuzzi, C.; Fegan, S. J.; Ferrara, E. C.; Focke, W. B.; Fukazawa, Y.; Fukui, Y.; Funk, S.; Fusco, P.; Gargano, F.; Gasparrini, D.; Germani, S.; Giglietto, N.; Giordano, F.; Giroletti, M.; Glanzman, T.; Godfrey, G.; Grenier, I. A.; Grondin, M. H.; Grove, J. E.; Guiriec, S.; Hadasch, D.; Hanabata, Y.; Harding, A. K.; Hayashi, K.; Horan, D.; Hou, X.; Hughes, R. E.; Itoh, R.; Jackson, M. S.; Jóhannesson, G.; Johnson, A. S.; Kamae, T.; Katagiri, H.; Kataoka, Jun; Knödlseder, J.; Kuss, M.; Lande, J.; Larsson, S.; Lee, S. H.; Lemoine-Goumard, M.; Longo, F.; Loparco, F.; Lovellette, M. N.; Lubrano, P.; Martin, P.; Mazziotta, M. N.; McEnery, J. E.; Mehault, J.; Michelson, P. F.; Mitthumsiri, W.; Mizuno, T.; Moiseev, A. A.; Monte, C.; Monzani, M. E.; Morselli, A.; Moskalenko, I. V.; Murgia, S.; Naumann-Godo, M.; Nemmen, R.; Nishino, S.; Norris, J. P.; Nuss, E.; Ohno, M.; Ohsugi, T.; Okumura, A.; Omodei, N.; Orlando, E.; Ormes, J. F.; Ozaki, M.; Paneque, D.; Panetta, J. H.; Parent, D.; Pesce-Rollins, M.; Pierbattista, M.; Piron, F.; Pivato, G.; Porter, T. A.; Rainò, S.; Rando, R.; Razzano, M.; Reimer, A.; Reimer, O.; Romoli, C.; Roth, M.; Sada, T.; Sadrozinski, H. F W; Sanchez, D. A.; Sbarra, C.; Sgrò, C.; Siskind, E. J.; Spandre, G.; Spinelli, P.; Strong, A. W.; Suson, D. J.; Takahashi, H.; Takahashi, T.; Tanaka, T.; Thayer, J. G.; Thayer, J. B.; Thompson, D. J.; Tibaldo, L.; Tibolla, O.; Tinivella, M.; Torres, D. F.; Tosti, G.; Tramacere, A.; Troja, E.; Uchiyama, Y.; Uehara, T.; Usher, T. L.; Vandenbroucke, J.; Vasileiou, V.; Vianello, G.; Vitale, V.; Waite, A. P.; Wang, P.; Winer, B. L.; Wood, K. S.; Yamamoto, H.; Yang, Z.; Zimmer, S.

    In: Astrophysical Journal, Vol. 755, No. 1, 22, 10.08.2012.

    Research output: Contribution to journalArticle

    Ackermann, M, Ajello, M, Allafort, A, Baldini, L, Ballet, J, Barbiellini, G, Bastieri, D, Bechtol, K, Bellazzini, R, Berenji, B, Blandford, RD, Bloom, ED, Bonamente, E, Borgland, AW, Bottacini, E, Brandt, TJ, Bregeon, J, Brigida, M, Bruel, P, Buehler, R, Busetto, G, Buson, S, Caliandro, GA, Cameron, RA, Caraveo, PA, Casandjian, JM, Cecchi, C, Charles, E, Chekhtman, A, Chiang, J, Ciprini, S, Claus, R, Cohen-Tanugi, J, Conrad, J, D'Ammando, F, De Angelis, A, De Palma, F, Dermer, CD, Digel, SW, Do Couto E Silva, E, Drell, PS, Drlica-Wagner, A, Falletti, L, Favuzzi, C, Fegan, SJ, Ferrara, EC, Focke, WB, Fukazawa, Y, Fukui, Y, Funk, S, Fusco, P, Gargano, F, Gasparrini, D, Germani, S, Giglietto, N, Giordano, F, Giroletti, M, Glanzman, T, Godfrey, G, Grenier, IA, Grondin, MH, Grove, JE, Guiriec, S, Hadasch, D, Hanabata, Y, Harding, AK, Hayashi, K, Horan, D, Hou, X, Hughes, RE, Itoh, R, Jackson, MS, Jóhannesson, G, Johnson, AS, Kamae, T, Katagiri, H, Kataoka, J, Knödlseder, J, Kuss, M, Lande, J, Larsson, S, Lee, SH, Lemoine-Goumard, M, Longo, F, Loparco, F, Lovellette, MN, Lubrano, P, Martin, P, Mazziotta, MN, McEnery, JE, Mehault, J, Michelson, PF, Mitthumsiri, W, Mizuno, T, Moiseev, AA, Monte, C, Monzani, ME, Morselli, A, Moskalenko, IV, Murgia, S, Naumann-Godo, M, Nemmen, R, Nishino, S, Norris, JP, Nuss, E, Ohno, M, Ohsugi, T, Okumura, A, Omodei, N, Orlando, E, Ormes, JF, Ozaki, M, Paneque, D, Panetta, JH, Parent, D, Pesce-Rollins, M, Pierbattista, M, Piron, F, Pivato, G, Porter, TA, Rainò, S, Rando, R, Razzano, M, Reimer, A, Reimer, O, Romoli, C, Roth, M, Sada, T, Sadrozinski, HFW, Sanchez, DA, Sbarra, C, Sgrò, C, Siskind, EJ, Spandre, G, Spinelli, P, Strong, AW, Suson, DJ, Takahashi, H, Takahashi, T, Tanaka, T, Thayer, JG, Thayer, JB, Thompson, DJ, Tibaldo, L, Tibolla, O, Tinivella, M, Torres, DF, Tosti, G, Tramacere, A, Troja, E, Uchiyama, Y, Uehara, T, Usher, TL, Vandenbroucke, J, Vasileiou, V, Vianello, G, Vitale, V, Waite, AP, Wang, P, Winer, BL, Wood, KS, Yamamoto, H, Yang, Z & Zimmer, S 2012, 'Fermi large area telescope study of cosmic rays and the interstellar medium in nearby molecular clouds', Astrophysical Journal, vol. 755, no. 1, 22. https://doi.org/10.1088/0004-637X/755/1/22
    Ackermann, M. ; Ajello, M. ; Allafort, A. ; Baldini, L. ; Ballet, J. ; Barbiellini, G. ; Bastieri, D. ; Bechtol, K. ; Bellazzini, R. ; Berenji, B. ; Blandford, R. D. ; Bloom, E. D. ; Bonamente, E. ; Borgland, A. W. ; Bottacini, E. ; Brandt, T. J. ; Bregeon, J. ; Brigida, M. ; Bruel, P. ; Buehler, R. ; Busetto, G. ; Buson, S. ; Caliandro, G. A. ; Cameron, R. A. ; Caraveo, P. A. ; Casandjian, J. M. ; Cecchi, C. ; Charles, E. ; Chekhtman, A. ; Chiang, J. ; Ciprini, S. ; Claus, R. ; Cohen-Tanugi, J. ; Conrad, J. ; D'Ammando, F. ; De Angelis, A. ; De Palma, F. ; Dermer, C. D. ; Digel, S. W. ; Do Couto E Silva, E. ; Drell, P. S. ; Drlica-Wagner, A. ; Falletti, L. ; Favuzzi, C. ; Fegan, S. J. ; Ferrara, E. C. ; Focke, W. B. ; Fukazawa, Y. ; Fukui, Y. ; Funk, S. ; Fusco, P. ; Gargano, F. ; Gasparrini, D. ; Germani, S. ; Giglietto, N. ; Giordano, F. ; Giroletti, M. ; Glanzman, T. ; Godfrey, G. ; Grenier, I. A. ; Grondin, M. H. ; Grove, J. E. ; Guiriec, S. ; Hadasch, D. ; Hanabata, Y. ; Harding, A. K. ; Hayashi, K. ; Horan, D. ; Hou, X. ; Hughes, R. E. ; Itoh, R. ; Jackson, M. S. ; Jóhannesson, G. ; Johnson, A. S. ; Kamae, T. ; Katagiri, H. ; Kataoka, Jun ; Knödlseder, J. ; Kuss, M. ; Lande, J. ; Larsson, S. ; Lee, S. H. ; Lemoine-Goumard, M. ; Longo, F. ; Loparco, F. ; Lovellette, M. N. ; Lubrano, P. ; Martin, P. ; Mazziotta, M. N. ; McEnery, J. E. ; Mehault, J. ; Michelson, P. F. ; Mitthumsiri, W. ; Mizuno, T. ; Moiseev, A. A. ; Monte, C. ; Monzani, M. E. ; Morselli, A. ; Moskalenko, I. V. ; Murgia, S. ; Naumann-Godo, M. ; Nemmen, R. ; Nishino, S. ; Norris, J. P. ; Nuss, E. ; Ohno, M. ; Ohsugi, T. ; Okumura, A. ; Omodei, N. ; Orlando, E. ; Ormes, J. F. ; Ozaki, M. ; Paneque, D. ; Panetta, J. H. ; Parent, D. ; Pesce-Rollins, M. ; Pierbattista, M. ; Piron, F. ; Pivato, G. ; Porter, T. A. ; Rainò, S. ; Rando, R. ; Razzano, M. ; Reimer, A. ; Reimer, O. ; Romoli, C. ; Roth, M. ; Sada, T. ; Sadrozinski, H. F W ; Sanchez, D. A. ; Sbarra, C. ; Sgrò, C. ; Siskind, E. J. ; Spandre, G. ; Spinelli, P. ; Strong, A. W. ; Suson, D. J. ; Takahashi, H. ; Takahashi, T. ; Tanaka, T. ; Thayer, J. G. ; Thayer, J. B. ; Thompson, D. J. ; Tibaldo, L. ; Tibolla, O. ; Tinivella, M. ; Torres, D. F. ; Tosti, G. ; Tramacere, A. ; Troja, E. ; Uchiyama, Y. ; Uehara, T. ; Usher, T. L. ; Vandenbroucke, J. ; Vasileiou, V. ; Vianello, G. ; Vitale, V. ; Waite, A. P. ; Wang, P. ; Winer, B. L. ; Wood, K. S. ; Yamamoto, H. ; Yang, Z. ; Zimmer, S. / Fermi large area telescope study of cosmic rays and the interstellar medium in nearby molecular clouds. In: Astrophysical Journal. 2012 ; Vol. 755, No. 1.
    @article{8df91d01fddb43548e1ff56a5a2dcf93,
    title = "Fermi large area telescope study of cosmic rays and the interstellar medium in nearby molecular clouds",
    abstract = "We report an analysis of the interstellar γ-ray emission from the Chamaeleon, R Coronae Australis (R CrA), and Cepheus and Polaris flare regions with the Fermi Large Area Telescope. They are among the nearest molecular cloud complexes, within 300pc from the solar system. The γ-ray emission produced by interactions of cosmic rays (CRs) and interstellar gas in those molecular clouds is useful to study the CR densities and distributions of molecular gas close to the solar system. The obtained γ-ray emissivities above 250MeV are (5.9 ± 0.1stat +0.9 -1.0sys) × 10-27photonss-1sr-1 H-atom-1, (10.2 ± 0.4stat +1.2 -1.7sys) × 10 -27photonss-1sr-1 H-atom-1, and (9.1 ± 0.3stat +1.5 -0.6sys) × 10 -27photonss-1sr-1 H-atom-1 for the Chamaeleon, R CrA, and Cepheus and Polaris flare regions, respectively. Whereas the energy dependences of the emissivities agree well with that predicted from direct CR observations at the Earth, the measured emissivities from 250MeV to 10 GeV indicate a variation of the CR density by 20{\%} in the neighborhood of the solar system, even if we consider systematic uncertainties. The molecular mass calibrating ratio, X CO = N(H2)/W CO, is found to be (0.96 ± 0.06stat +0.15 -0.12sys) × 1020 H2-moleculecm-2 (Kkms -1)-1, (0.99 ± 0.08stat +0.18 -0.10sys) × 1020 H2-moleculecm -2 (Kkms-1)-1, and (0.63 ± 0.02 stat +0.09 -0.07sys) × 1020 H2-moleculecm-2 (Kkms-1)-1 for the Chamaeleon, R CrA, and Cepheus and Polaris flare regions, respectively, suggesting a variation of X CO in the vicinity of the solar system. From the obtained values of X CO, the masses of molecular gas traced by W CO in the Chamaeleon, R CrA, and Cepheus and Polaris flare regions are estimated to be 5 × 103 M, 103 M, and 3.3 × 104 M ,respectively. A comparable amount of gas not traced well by standard H I and CO surveys is found in the regions investigated.",
    keywords = "cosmic rays, gamma rays: ISM",
    author = "M. Ackermann and M. Ajello and A. Allafort and L. Baldini and J. Ballet and G. Barbiellini and D. Bastieri and K. Bechtol and R. Bellazzini and B. Berenji and Blandford, {R. D.} and Bloom, {E. D.} and E. Bonamente and Borgland, {A. W.} and E. Bottacini and Brandt, {T. J.} and J. Bregeon and M. Brigida and P. Bruel and R. Buehler and G. Busetto and S. Buson and Caliandro, {G. A.} and Cameron, {R. A.} and Caraveo, {P. A.} and Casandjian, {J. M.} and C. Cecchi and E. Charles and A. Chekhtman and J. Chiang and S. Ciprini and R. Claus and J. Cohen-Tanugi and J. Conrad and F. D'Ammando and {De Angelis}, A. and {De Palma}, F. and Dermer, {C. D.} and Digel, {S. W.} and {Do Couto E Silva}, E. and Drell, {P. S.} and A. Drlica-Wagner and L. Falletti and C. Favuzzi and Fegan, {S. J.} and Ferrara, {E. C.} and Focke, {W. B.} and Y. Fukazawa and Y. Fukui and S. Funk and P. Fusco and F. Gargano and D. Gasparrini and S. Germani and N. Giglietto and F. Giordano and M. Giroletti and T. Glanzman and G. Godfrey and Grenier, {I. A.} and Grondin, {M. H.} and Grove, {J. E.} and S. Guiriec and D. Hadasch and Y. Hanabata and Harding, {A. K.} and K. Hayashi and D. Horan and X. Hou and Hughes, {R. E.} and R. Itoh and Jackson, {M. S.} and G. J{\'o}hannesson and Johnson, {A. S.} and T. Kamae and H. Katagiri and Jun Kataoka and J. Kn{\"o}dlseder and M. Kuss and J. Lande and S. Larsson and Lee, {S. H.} and M. Lemoine-Goumard and F. Longo and F. Loparco and Lovellette, {M. N.} and P. Lubrano and P. Martin and Mazziotta, {M. N.} and McEnery, {J. E.} and J. Mehault and Michelson, {P. F.} and W. Mitthumsiri and T. Mizuno and Moiseev, {A. A.} and C. Monte and Monzani, {M. E.} and A. Morselli and Moskalenko, {I. V.} and S. Murgia and M. Naumann-Godo and R. Nemmen and S. Nishino and Norris, {J. P.} and E. Nuss and M. Ohno and T. Ohsugi and A. Okumura and N. Omodei and E. Orlando and Ormes, {J. F.} and M. Ozaki and D. Paneque and Panetta, {J. H.} and D. Parent and M. Pesce-Rollins and M. Pierbattista and F. Piron and G. Pivato and Porter, {T. A.} and S. Rain{\`o} and R. Rando and M. Razzano and A. Reimer and O. Reimer and C. Romoli and M. Roth and T. Sada and Sadrozinski, {H. F W} and Sanchez, {D. A.} and C. Sbarra and C. Sgr{\`o} and Siskind, {E. J.} and G. Spandre and P. Spinelli and Strong, {A. W.} and Suson, {D. J.} and H. Takahashi and T. Takahashi and T. Tanaka and Thayer, {J. G.} and Thayer, {J. B.} and Thompson, {D. J.} and L. Tibaldo and O. Tibolla and M. Tinivella and Torres, {D. F.} and G. Tosti and A. Tramacere and E. Troja and Y. Uchiyama and T. Uehara and Usher, {T. L.} and J. Vandenbroucke and V. Vasileiou and G. Vianello and V. Vitale and Waite, {A. P.} and P. Wang and Winer, {B. L.} and Wood, {K. S.} and H. Yamamoto and Z. Yang and S. Zimmer",
    year = "2012",
    month = "8",
    day = "10",
    doi = "10.1088/0004-637X/755/1/22",
    language = "English",
    volume = "755",
    journal = "Astrophysical Journal",
    issn = "0004-637X",
    publisher = "IOP Publishing Ltd.",
    number = "1",

    }

    TY - JOUR

    T1 - Fermi large area telescope study of cosmic rays and the interstellar medium in nearby molecular clouds

    AU - Ackermann, M.

    AU - Ajello, M.

    AU - Allafort, A.

    AU - Baldini, L.

    AU - Ballet, J.

    AU - Barbiellini, G.

    AU - Bastieri, D.

    AU - Bechtol, K.

    AU - Bellazzini, R.

    AU - Berenji, B.

    AU - Blandford, R. D.

    AU - Bloom, E. D.

    AU - Bonamente, E.

    AU - Borgland, A. W.

    AU - Bottacini, E.

    AU - Brandt, T. J.

    AU - Bregeon, J.

    AU - Brigida, M.

    AU - Bruel, P.

    AU - Buehler, R.

    AU - Busetto, G.

    AU - Buson, S.

    AU - Caliandro, G. A.

    AU - Cameron, R. A.

    AU - Caraveo, P. A.

    AU - Casandjian, J. M.

    AU - Cecchi, C.

    AU - Charles, E.

    AU - Chekhtman, A.

    AU - Chiang, J.

    AU - Ciprini, S.

    AU - Claus, R.

    AU - Cohen-Tanugi, J.

    AU - Conrad, J.

    AU - D'Ammando, F.

    AU - De Angelis, A.

    AU - De Palma, F.

    AU - Dermer, C. D.

    AU - Digel, S. W.

    AU - Do Couto E Silva, E.

    AU - Drell, P. S.

    AU - Drlica-Wagner, A.

    AU - Falletti, L.

    AU - Favuzzi, C.

    AU - Fegan, S. J.

    AU - Ferrara, E. C.

    AU - Focke, W. B.

    AU - Fukazawa, Y.

    AU - Fukui, Y.

    AU - Funk, S.

    AU - Fusco, P.

    AU - Gargano, F.

    AU - Gasparrini, D.

    AU - Germani, S.

    AU - Giglietto, N.

    AU - Giordano, F.

    AU - Giroletti, M.

    AU - Glanzman, T.

    AU - Godfrey, G.

    AU - Grenier, I. A.

    AU - Grondin, M. H.

    AU - Grove, J. E.

    AU - Guiriec, S.

    AU - Hadasch, D.

    AU - Hanabata, Y.

    AU - Harding, A. K.

    AU - Hayashi, K.

    AU - Horan, D.

    AU - Hou, X.

    AU - Hughes, R. E.

    AU - Itoh, R.

    AU - Jackson, M. S.

    AU - Jóhannesson, G.

    AU - Johnson, A. S.

    AU - Kamae, T.

    AU - Katagiri, H.

    AU - Kataoka, Jun

    AU - Knödlseder, J.

    AU - Kuss, M.

    AU - Lande, J.

    AU - Larsson, S.

    AU - Lee, S. H.

    AU - Lemoine-Goumard, M.

    AU - Longo, F.

    AU - Loparco, F.

    AU - Lovellette, M. N.

    AU - Lubrano, P.

    AU - Martin, P.

    AU - Mazziotta, M. N.

    AU - McEnery, J. E.

    AU - Mehault, J.

    AU - Michelson, P. F.

    AU - Mitthumsiri, W.

    AU - Mizuno, T.

    AU - Moiseev, A. A.

    AU - Monte, C.

    AU - Monzani, M. E.

    AU - Morselli, A.

    AU - Moskalenko, I. V.

    AU - Murgia, S.

    AU - Naumann-Godo, M.

    AU - Nemmen, R.

    AU - Nishino, S.

    AU - Norris, J. P.

    AU - Nuss, E.

    AU - Ohno, M.

    AU - Ohsugi, T.

    AU - Okumura, A.

    AU - Omodei, N.

    AU - Orlando, E.

    AU - Ormes, J. F.

    AU - Ozaki, M.

    AU - Paneque, D.

    AU - Panetta, J. H.

    AU - Parent, D.

    AU - Pesce-Rollins, M.

    AU - Pierbattista, M.

    AU - Piron, F.

    AU - Pivato, G.

    AU - Porter, T. A.

    AU - Rainò, S.

    AU - Rando, R.

    AU - Razzano, M.

    AU - Reimer, A.

    AU - Reimer, O.

    AU - Romoli, C.

    AU - Roth, M.

    AU - Sada, T.

    AU - Sadrozinski, H. F W

    AU - Sanchez, D. A.

    AU - Sbarra, C.

    AU - Sgrò, C.

    AU - Siskind, E. J.

    AU - Spandre, G.

    AU - Spinelli, P.

    AU - Strong, A. W.

    AU - Suson, D. J.

    AU - Takahashi, H.

    AU - Takahashi, T.

    AU - Tanaka, T.

    AU - Thayer, J. G.

    AU - Thayer, J. B.

    AU - Thompson, D. J.

    AU - Tibaldo, L.

    AU - Tibolla, O.

    AU - Tinivella, M.

    AU - Torres, D. F.

    AU - Tosti, G.

    AU - Tramacere, A.

    AU - Troja, E.

    AU - Uchiyama, Y.

    AU - Uehara, T.

    AU - Usher, T. L.

    AU - Vandenbroucke, J.

    AU - Vasileiou, V.

    AU - Vianello, G.

    AU - Vitale, V.

    AU - Waite, A. P.

    AU - Wang, P.

    AU - Winer, B. L.

    AU - Wood, K. S.

    AU - Yamamoto, H.

    AU - Yang, Z.

    AU - Zimmer, S.

    PY - 2012/8/10

    Y1 - 2012/8/10

    N2 - We report an analysis of the interstellar γ-ray emission from the Chamaeleon, R Coronae Australis (R CrA), and Cepheus and Polaris flare regions with the Fermi Large Area Telescope. They are among the nearest molecular cloud complexes, within 300pc from the solar system. The γ-ray emission produced by interactions of cosmic rays (CRs) and interstellar gas in those molecular clouds is useful to study the CR densities and distributions of molecular gas close to the solar system. The obtained γ-ray emissivities above 250MeV are (5.9 ± 0.1stat +0.9 -1.0sys) × 10-27photonss-1sr-1 H-atom-1, (10.2 ± 0.4stat +1.2 -1.7sys) × 10 -27photonss-1sr-1 H-atom-1, and (9.1 ± 0.3stat +1.5 -0.6sys) × 10 -27photonss-1sr-1 H-atom-1 for the Chamaeleon, R CrA, and Cepheus and Polaris flare regions, respectively. Whereas the energy dependences of the emissivities agree well with that predicted from direct CR observations at the Earth, the measured emissivities from 250MeV to 10 GeV indicate a variation of the CR density by 20% in the neighborhood of the solar system, even if we consider systematic uncertainties. The molecular mass calibrating ratio, X CO = N(H2)/W CO, is found to be (0.96 ± 0.06stat +0.15 -0.12sys) × 1020 H2-moleculecm-2 (Kkms -1)-1, (0.99 ± 0.08stat +0.18 -0.10sys) × 1020 H2-moleculecm -2 (Kkms-1)-1, and (0.63 ± 0.02 stat +0.09 -0.07sys) × 1020 H2-moleculecm-2 (Kkms-1)-1 for the Chamaeleon, R CrA, and Cepheus and Polaris flare regions, respectively, suggesting a variation of X CO in the vicinity of the solar system. From the obtained values of X CO, the masses of molecular gas traced by W CO in the Chamaeleon, R CrA, and Cepheus and Polaris flare regions are estimated to be 5 × 103 M, 103 M, and 3.3 × 104 M ,respectively. A comparable amount of gas not traced well by standard H I and CO surveys is found in the regions investigated.

    AB - We report an analysis of the interstellar γ-ray emission from the Chamaeleon, R Coronae Australis (R CrA), and Cepheus and Polaris flare regions with the Fermi Large Area Telescope. They are among the nearest molecular cloud complexes, within 300pc from the solar system. The γ-ray emission produced by interactions of cosmic rays (CRs) and interstellar gas in those molecular clouds is useful to study the CR densities and distributions of molecular gas close to the solar system. The obtained γ-ray emissivities above 250MeV are (5.9 ± 0.1stat +0.9 -1.0sys) × 10-27photonss-1sr-1 H-atom-1, (10.2 ± 0.4stat +1.2 -1.7sys) × 10 -27photonss-1sr-1 H-atom-1, and (9.1 ± 0.3stat +1.5 -0.6sys) × 10 -27photonss-1sr-1 H-atom-1 for the Chamaeleon, R CrA, and Cepheus and Polaris flare regions, respectively. Whereas the energy dependences of the emissivities agree well with that predicted from direct CR observations at the Earth, the measured emissivities from 250MeV to 10 GeV indicate a variation of the CR density by 20% in the neighborhood of the solar system, even if we consider systematic uncertainties. The molecular mass calibrating ratio, X CO = N(H2)/W CO, is found to be (0.96 ± 0.06stat +0.15 -0.12sys) × 1020 H2-moleculecm-2 (Kkms -1)-1, (0.99 ± 0.08stat +0.18 -0.10sys) × 1020 H2-moleculecm -2 (Kkms-1)-1, and (0.63 ± 0.02 stat +0.09 -0.07sys) × 1020 H2-moleculecm-2 (Kkms-1)-1 for the Chamaeleon, R CrA, and Cepheus and Polaris flare regions, respectively, suggesting a variation of X CO in the vicinity of the solar system. From the obtained values of X CO, the masses of molecular gas traced by W CO in the Chamaeleon, R CrA, and Cepheus and Polaris flare regions are estimated to be 5 × 103 M, 103 M, and 3.3 × 104 M ,respectively. A comparable amount of gas not traced well by standard H I and CO surveys is found in the regions investigated.

    KW - cosmic rays

    KW - gamma rays: ISM

    UR - http://www.scopus.com/inward/record.url?scp=84864453553&partnerID=8YFLogxK

    UR - http://www.scopus.com/inward/citedby.url?scp=84864453553&partnerID=8YFLogxK

    U2 - 10.1088/0004-637X/755/1/22

    DO - 10.1088/0004-637X/755/1/22

    M3 - Article

    VL - 755

    JO - Astrophysical Journal

    JF - Astrophysical Journal

    SN - 0004-637X

    IS - 1

    M1 - 22

    ER -