RADIO PHYSICS AND RADIO ASTRONOMY

PACS numbers: 95.85.Bh,
97.10.Bt, 98.38.Er 

Purpose: The statistical features of emission in CS (J = 2 - 1) line, Class II methanol masers and IR sources in the regions associated with the Class II methanol masers are studied.

Design/methodology/approach: The survey is performed at the CS (J = 2 - 1) line transition frequency, since this molecule is a solid gas tracer in which the conditions for the existence of methanol masers should arise.

Findings: For the sources with which the Class II methanol masers are associated the dependences logLSC - logLbol , logLmeth - logLSC, and logLmeth - logLbol have been found. It is shown that on the average, the emission in the CS (J = 2 - 1) line toward Class II methanol masers is more often detected in those sources which are associated with the higher bolometric luminosity IR sources.

Conclusions: The survey of the emission in the CS (J = 2 - 1) line toward Class II methanol masers for the northern celestial hemisphere was carried out. The statistical features of the emission in the CS (J = 2 - 1) line, Class II methanol masers and IR sources are shown.

Key words: methanol masers, CS, dense cores, star formation

Radio phys. radio astron. 2017, 22(3): 173-200

REFERENCES

 1.  MENTEN, K., 1991. Methanol Masers and Submillimeter WavelengthWater Masers in Star-Forming Regions. In: Atoms, Ions and Molecules: New Results in Spectral Line Astrophysics, ASP Conference Series. vol. 16, pp. 119–136.

2. BATRLA, W., MATTHEWS, H. E., MENTEN, K. M. and WALMSLEY, C. M., 1987. Detection of strong methanol masers towards galactic H II regions. Nature. vol. 326, no. 6108, pp. 49–51. DOI: https://doi.org/10.1038/326049a0

3. BRONFMAN, L., NYMAN, L.-A. and MAY, J., 1996. A CS (2-1) Survey of IRAS Point Sources With Color Characteristics of Ultra-Compact H II Regions. Astron. Astrophys. Suppl. Ser. vol. 115, pp. 1–81.

4. MOLINARI, S., BRAND, J., CESARONI, R. and PALLA, F., 1996. A Search for Precursors of Ultracompact H II Regions in a Sample of Luminous IRAS Sources. I. Association with Ammonia Cores. Astron. Astrophys. vol. 308, pp. 573–587.

5. BEUTHER, H., SCHILKE, P., MENTEN, K. M., MOTTE, F., SRIDHARAN, T. K. and WYROWSKI, F., 2002. High-Mass Protostellar Candidates. II. Density Structure from Dust Continuum and CS Emission. Astrophys. J. vol. 566, no. 2, pp. 945–965. DOI: https://doi.org/10.1086/338334

6. JIJINA, J., MYERS, P. C., and ADAMS, F. C., 1999. Dense Cores Mapped in Ammonia: A Database. Astrophys. J. Suppl. Ser. vol. 125, no.1, pp. 161–236. DOI: https://doi.org/10.1086/313268

7. MOTTRAM, J. C., HOARE, M. G., URQUHART, J. S., LUMSDEN, S. L., OUDMAIJER, R. D., ROBITAILLE, T. P., MOORE, T. J. T., DAVIES, B. and STEAD, J., 2011. The Red MSX Source Survey: the Bolometric Fluxes and Luminosity Distributions of Young Massive Stars. Astron. Astrophys. vol. 525, id. A149. DOI: https://doi.org/10.1051/0004-6361/201014479

8. ZINCHENKO, I., FORSSTROEM, V., LAPINOV, A. and
MATTILA, K., 1994. Studies of Dense Molecular Cores in Regions of Massive Star Formation. CS (J=2-1) and HCN (J=1–0) Observations of 11 Northern Cores. Astron. Astrophys. vol. 288, pp. 601–616.

9. CESARONI, R., FELLI, M. and WALMSLEY, C. M., 1999. High Density Molecular Clumps Around Protostellar Candidates. Astron. Astrophys. Suppl. Ser. vol. 136, no. 2, pp. 333–361. DOI: https://doi.org/10.1051/aas:1999218

10. SHIRLEY, Y. L., EVANS, N. J., YOUNG, K. E., KNEZ, C. and JAFFE, D. T., 2003. A CS (J=5–4) Mapping Survey Toward High-Mass Star-forming Cores Associated with Water Masers. Astrophys. J. Suppl. Ser. vol. 149, no. 2, pp. 375–403. DOI: https://doi.org/10.1086/379147

11. WU, J., EVANS, N. J., SHIRLEY, Y. L. and KNEZ, C., 2010. The Properties of Massive, Dense Clumps: Mapping Surveys of HCN and CS. Astrophys. J. Suppl. Ser. vol. 188, no. 2, pp. 313–357. DOI: 10.1088/ 0067-0049/188/2/313

12. JUVELA, M., 1996. Studies of Dense Molecular Cores in Regions of Massive Star Formation. IV. Multitransition CS-Study Towards Southern  H₂O Masers in the Longitude Range l=308–360 deg. Astron. Astrophys. Suppl. Ser. vol. 118, pp. 191–226. DOI: https://doi.org/10.1051/aas:1996190

13. HARJU, J., LEHTINEN, K., BOOTH, R. S. and ZINCHENKO, I., 1998. A Survey of SiO Emission Towards Interstellar Masers – I. SiO Line Characteristics. Astron. Astrophys. Suppl. Ser. vol. 132, no. 2, pp. 211–231. DOI: https://doi.org/10.1051/aas:1998448

14. ANGLADA, G., ESTALELLA, R., PASTOR, J., RODRIGUEZ, L. F. and HASCHICK, A. D., 1996. A CS and NH3 Survey of Regions with H₂O  Maser Emission. Astrophys. J. vol. 463, pp. 205–223. DOI: https://doi.org/10.1086/177235

15. SZYMCZAK, M., PILLAI, T. and MENTEN, K. M., 2005. Masers as Signposts of High-Mass Protostars. A Water Maser Survey of Methanol Maser Sources. Astron. Astrophys. vol. 434, no. 2, pp. 613–621. DOI: https://doi.org/10.1051/0004-6361:20042437

16. LARIONOV, G. M., VAL'TTS, I. E., WINNBERG, A., JOHANSSON, L. E. B., BOOTH, R. S. and GOLUBEV, V. V., 1999. Survey of Bipolar Outflows and Methanol Masers in the C³²S (2-1) and C³⁴S (2-1) Lines in the Northern Sky. Astron. Astrophys. Suppl. Ser. vol. 139, no. 2, pp. 257–275. DOI: https://doi.org/10.1051/aas:1999392

17. VAL'TTS, I. E. and LARIONOV, G. M., 2007. A General Catalog of Class I Methanol Masers. Astron. Rep. vol. 51, no. 7, pp. 519–530. DOI: https://doi.org/10.1134/S1063772907070013

18. BAYANDINA, O. S., VAL'TTS, I. E. and LARIONOV, G. M., 2012. Class I Methanol Maser Emission in Infrared Clouds and the Third Version of the Astro Space Center MMI/SFR Catalog. Astron. Rep. vol. 56, no. 7, pp. 553–563. DOI: https://doi.org/10.1134/S1063772912060029

19. PESTALOZZI, M. R., MINIER, V. and BOOTH, R. S., 2005. A General Catalogue of 6.7-GHz Methanol Masers: I. Data. Astron. Astrophys. vol. 432, no. 2, pp. 737–742. DOI: https://doi.org/10.1051/0004-6361:20035855

20. GAN, C.-G., CHEN, X., SHEN, Z.-Q., XU, Y. and JU, B.-G., 2013. A Search for 95 GHz Class I Methanol Masers in Molecular Outflows. Astrophys. J. vol. 763, no. 1, id. 2. DOI: https://doi.org/10.1088/0004-637X/763/1/2

21. CHEN, X., ELLINGSEN, S. P., SHEN, Z.-Q., TITMARSH, A. and GAN, C.-G., 2011. A 95 GHz Class I Methanol Maser Survey Toward Glimpse Extended Green Objects (EGOs). Astrophys. J. Suppl. Ser. vol. 196, no. 1, id. 9. DOI: https://doi.org/10.1088/0067-0049/196/1/9

22. XU, Y., ZHENG, X.-W. and JIANG, D.-R., 2003. Statistical Properties of 6.7 GHz Methanol Maser Sources. Chin. J. Astro. Astrophys. vol. 3, no. 1, pp. 49–68. DOI: https://doi.org/10.1088/1009-9271/3/1/49

23. PIDDYACHIY, V. I., SHULGA, V. M., KOROLEV, A. M. and MYSHENKO, V. V., 2005. High Doping Density Schottky Diodes in the 3mm Wavelength Cryogenic Heterodyne Receiver. Int. J. Infrared Millimeter Waves. vol. 26, no. 9, pp. 1307–1315. DOI: 10.1007/10762-005-7605-6

24. KUTNER, M. L. and ULICH, B. L., 1981. Recommendations for Calibration of Millimeter-Wavelength Spectral Line Data. Astrophys. J. vol. 250, pp. 341–348. DOI: https://doi.org/10.1086/159380

25. ANTYUFEYEV, O. V. and SHULGA, V. M., 2005. PC Based Spectrum Analyzer. Radiotekhnika. vol. 10, pp. 145–148 (in Russian).

26. ANTYUFEYEV, O. V., ZUBRIN, S. Y., KOROL, A. M., KOROLEV, A. M., MYSHENKO, V. V., PIDDYACHIY, V. I., POLADICH, A. V., SHKODIN, V. I. and SHULGA, V. M., 2010. Instrumental Complex for Spectral Observations at 85 to 116 GHz at the CrAO RT-22 Radio Telescope. Radio Phys. Radio Astron. vol. 15, no. 4, pp. 369–375 (in Russian).

27. SZYMCZAK, M., HRYNEK, G. and KUS, A. J., 2000. A Survey of the 6.7 GHz Methanol Maser Emission from IRAS Sources – I. Data. Astron. Astrophys. Suppl. Ser. vol. 143, no. 2, pp. 269–301. DOI: https://doi.org/10.1051/aas:2000334

28. FONTANI, F., CESARONI, R. and FURUYA, R. S., 2010. Class I and Class II Methanol Masers in High-Mass Star-Forming Regions. Astron. Astrophys. vol. 517, id. A56. DOI: https://doi.org/10.1051/0004-6361/200913679

29. BLASZKIEWICZ, L. and KUS, A. J., 2004. 12.2 GHz Survey Towards 6.7 GHz Methanol Masers – A Comparison of 12.2 GHz and 6.7 GHz Spectra. Astron. Astrophys. vol. 413, no. 1, pp. 233–240. DOI: https://doi.org/10.1051/0004-6361:20031451

31. MINIER, V., CONWAY, J. E. and BOOTH, R. S., 2001. VLBI Observations of 6.7 and 12.2 GHz Methanol Masers Toward High Mass Star-Forming Regions. II. Tracing Massive Protostars. Astron. Astrophys. vol. 369, no. 1, pp. 278–290. DOI: https://doi.org/10.1051/0004-6361:20010124

32. CASWELL, J. L., YI, J., BOOTH, R. S. and CRAGG, D. M., 2000. Methanol Masers at 107.0 and 156.6 GHz. Mon. Not. R. Astron. Soc. vol. 313, no. 3, pp. 599–616. DOI: https://doi.org/10.1046/j.1365-8711.2000.03277.x

33. SZYMCZAK, M., KUS, A. J., HRYNEK, G., KĚPA, A. and PAZDERSKI, E., 2002. 6.7 GHz Methanol Masers at Sites of Star Formation. A Blind Survey of the Galactic Plane Between 20°≤l≤40° and |b|≤0.52°. Astron. Astrophys. vol. 392, no. 1, pp. 277–286. DOI: https://doi.org/10.1051/0004-6361:20020907

34. CASWELL, J. L., VAILE, R. A., ELLINGSEN, S. P. and NORRIS, R. P., 1995. Galactic Methanol Masers at 12 GHz. Mon. Not. R. Astron. Soc. vol. 274, no. 4, pp. 1126–1152. DOI: https://doi.org/10.1093/mnras/274.4.1126

35. PANDIAN, J. D., GOLDSMITH, P. F. and DESHPANDE, A. A., 2007. The Arecibo Methanol Maser Galactic Plane Survey. I. Data. Astrophys. J. vol. 656, no. 1, pp. 255–274. DOI: https://doi.org/10.1086/510512

36. SZYMCZAK, M., WOLAK, P., BARTKIEWICZ, A. and BORKOWSKI, K., 2012. The Torun Catalogue of 6.7 GHz Methanol Masers. Astron. Nachr. vol. 333, no. 7, pp. 634–639. DOI: https://doi.org/10.1002/asna.201211702

37. CATARZI, M., MOSCADELLI, L. and PANELLA, D., 1993. Observation of Methanol Maser Sources With the Arcetri 12 GHz Receiver. Astron. Astrophys. Suppl. Ser. vol. 98, no. 1, pp. 127–135.

38. WILSON, T. L., WALMSLEY, C. M., JEWELL, P. R. and SNYDER, L. E., 1984. Detection of a New Type of Methanol Maser. Astron. Astrophys. vol. 134, pp. L7–L10.

39. WILSON, T. L., WALMSLEY, C. M., MENTEN, K. M. and HERMSEN, W., 1985. The Discovery of a New Masering Transition of Interstellar Methanol. Astron. Astrophys. vol. 147, pp. L19–L22.

40. PESTALOZZI, M. R., MINIER, V., MOTTE, F. and CONWAY, J. E., 2006. Discovery of Two New Methanol Masers in NGC 7538. Locating of Massive Protostars. Astron. Astrophys. vol. 448, no. 3, pp. L57–L60. DOI: https://doi.org/10.1051/0004-6361:200600006

41. RYGL, K. L. J., BRUNTHALER, A., REID, M. J., MENTEN, K. M., VAN LANGEVELDE, H. J. and XU, Y., 2010. Trigonometric Parallaxes of 6.7 GHz Methanol Masers. Astron. Astrophys. vol. 511, id. A2. DOI: https://doi.org/10.1051/0004-6361/200913135

42. SCHENCK, D. E., SHIRLEY, Y. L., REITER, M. and JUNEAU, S., 2011. Testing the Global Star Formation Relation: An HCO⁺ (3-2) Mapping Study of Red MSX Sources in the Bolocam Galactic Plane Survey. Astron. J. vol. 142, no. 3, id. 94. DOI: 0.1088/0004-6256/142/3/94

43. SATO, M., HIROTA, T., HONMA, M., KOBAYASHI, H., SASAO, T., BUSHIMATA, T., CHOI, Y. K., IMAI, H., IWADATE, K., JIKE, T., KAMENO, S., KAMEYA, O., KAMOHARA, R., KAN-YA, Y., KAWAGUCHI, N., KIM, M. K., KUJI, S., KURAYAMA, T., MANABE, S., MATSUI, M., MATSUMOTO, N., MIYAJI, T., NAGAYAMA, T., NAKAGAWA, A., NAKAMURA, K., OH, C. S., OMODAKA, T., OYAMA, T., SAKAI, S., SATO, K., SHIBATA, K. M., TAMURA, Y. and YAMASHITA, K., 2008. Distance to NGC 281 in a Galactic Fragmenting Superbubble: Parallax Measurements with VERA. Publ. Astron. So. Jpn. vol. 60, is 5, 575–989. DOI: https://doi.org/10.1093/pasj/60.5.975

44. LUMSDEN, S. L., HOARE, M. G., URQUHART, J. S., OUDMAIJER, R. D., DAVIES, B., MOTTRAM, J. C., COOPER, H. D. B. and MOORE, T. J. T., 2013. The Red MSX Source Survey: The Massive Young Stellar Population of Our Galaxy. Astrophys. J. Suppl. Ser. vol. 208, no. 1, id. 11. DOI: https://doi.org/10.1088/0067-0049/208/1/11

45. WOUTERLOOT, J. G. A. and BRAND, J., 1989. IRAS Sources Beyond the Solar Circle. I. CO Observations. Astron. Astrophys. Suppl. Ser. vol. 80, no. 2, pp. 149–187.

46. HIROTA, T., BUSHIMATA, T., CHOI, Y. K., HONMA, M., IMAI, H., IWADATE, K., JIKE, T., KAMENO, S., KAMEYA, O., KAMOHARA, R., KAN-YA, Y., KAWAGUCHI, N., KIJIMA, M., KIM, M. K., KOBAYASHI, H., KUJI, S., KURAYAMA, T., MANABE, S., MARUYAMA, K., MATSUI, M., MATSUMOTO, N., MIYAJI, T., NAGAYAMA, T., NAKAGAWA, A., NAKAMURA, K., OH, C. S., OMODAKA, T., OYAMA, T., SAKAI, S., SASAO, T., SATO, K., SATO, M., SHIBATA, K. M., SHINTANI, M., TAMURA, Y., TSUSHIMA, M. and YAMASHITA, K., 2007. Distance to Orion KL Measured with VERA. Publ. Astron. Soc. Jpn. vol. 59, is. 5, pp. 897–903. DOI: https://doi.org/10.1093/pasj/59.5.897

47. HUGHES, V. A. and MACLEOD, G. C., 1993. A Comparison of the Infrared Luminosity and Ionizing Luminosity of Selected Star Forming Regions. Astron. J. vol. 105, no. 4, pp. 1495–1504. DOI: https://doi.org/10.1086/116528

48. HOU, L. G. and HAN, J. L., 2014. The Observed Spiral Structure of the Milky Way. Astron. Astrophys. vol. 569, id. A125. DOI: https://doi.org/10.1051/0004-6361/201424039

49. OH, C. S., KOBAYASHI, H., HONMA, M., HIROTA, T., SATO, K. and UENO, Y., 2010. VERA Observations of H₂O Maser Sources in Three Massive Star-Forming Regions and Galactic Rotation Measurements. Publ. Astron. Soc. Jpn. vol. 62, is. 1, pp. 101–114. DOI: https://doi.org/10.1093/pasj/62.1.101

50. NIINUMA, K., NAGAYAMA, T., HIROTA, T., HONMA, M., MOTOGI, K., NAKAGAWA, A., KURAYAMA, T., KAN-YA, Y., KAWAGUCHI, N., KOBAYASHI, H. and UENO, Y., 2011. Astrometry of H₂O Masers in the Massive Star-Forming Region IRAS 06061+2151 with VERA. Publ. Astron. Soc. Jpn. vol. 63, is. 1, pp. 9–16. DOI: https://doi.org/10.1093/pasj/63.1.9

51. BURNS, R. A., HANDA, T., NAGAYAMA, T., SUNADA, K. and OMODAKA, T., 2016. H₂O Masers in a Jet-Driven Bow Shock: Episodic Ejection from a Massive Young Stellar Object. Mon. Not. R. Astron. Soc. vol. 460, is. 1, pp. 283–290. DOI: https://doi.org/10.1093/mnras/stw958

52. HONMA, M., BUSHIMATA, T., CHOI, Y. K., HIROTA, T., IMAI, H., IWADATE, K., JIKE, T., KAMEYA, O., KAMOHARA, R., KAN-YA, Y., KAWAGUCHI, N., KIJIMA, M., KOBAYASHI, H., KUJI, S., KURAYAMA, T., MANABE, S., MIYAJI, T., NAGAYAMA, T., NAKAGAWA, A., OH, C. S., OMODAKA, T., OYAMA, T., SAKAI, S., SATO, K., SASAO, T., SHIBATA, K. M., SHINTANI, M., SUDA, H., TAMURA, Y., TSUSHIMA, M. and YAMASHITA, K., 2007. Astrometry of Galactic Star-Forming Region Sharpless 269 with VERA: Parallax Measurements and Constraint on Outer Rotation Curve. Publ. Astron. Soc. Jpn. vol. 59, is. 5, pp. 889–895. DOI: https://doi.org/10.1093/pasj/59.5.889

53. ZHANG, B., MOSCADELLI, L., SATO, M., REID, M. J., MENTEN, K. M., ZHENG, X. W., BRUNTHALER, A., DAME, T. M., XU, Y. and IMMER, K., 2014. The Parallax of W43: a Massive Star-forming Complex near the Galactic Bar. Astrophys. J. vol. 781, no. 2, id. 89. DOI: https://doi.org/10.1088/0004-637X/781/2/89

54. MOISÉS, A. P., DAMINELI, A., FIGUERÊDO, E., BLUM, R. D., CONTI, P. S. and BARBOSA, C. L., 2011. Spectrophotometric Distances to Galactic H II Regions. Mon. Not. R. Astron. Soc. vol. 411, no. 2, pp. 705–760. DOI: https://doi.org/10.1111/j.1365-2966.2010.17713.x

55. WU, Y. W., SATO, M., REID, M. J., MOSCADELLI, L., ZHANG, B., XU, Y., BRUNTHALER, A., MENTEN, K. M., DAME, T. M. and ZHENG, X. W., 2014. Trigonometric Parallaxes of Star-Forming Regions in the Sagittarius Spiral Arm. Astron. Astrophys. vol. 566, id. A17. DOI: https://doi.org/10.1051/0004-6361/201322765

56. ANDERSON, L. D., BANIA, T. M., BALSER, D. S., CUNNINGHAM, V., WENGER, T. V., JOHNSTONE, B. M. and ARMENTROUT, W. P., 2014. The WISE Catalog of Galactic H II Regions. Astrophys. J. Suppl. Ser. vol. 212, no. 1, id. 1. DOI: https://doi.org/10.1088/0067-0049/212/1/1

57. TRAFICANTE, A., FULLER, G. A., PERETTO, N., PINEDA, J. E. and MOLINARI, S., 2015. The Initial Conditions of Stellar Protocluster Formation - II. A Catalogue of Starless and Protostellar Clumps Embedded in IRDCs in the Galactic Longitude Range 15°≤l≤55°. Mon. Not. R. Astron. Soc. vol. 451, no. 3, pp. 3089–3106. DOI: https://doi.org/10.1093/mnras/stv1158

58. FAÚNDEZ, S., BRONFMAN, L., GARAY, G., CHINI, R., NYMAN, L.-Å. and MAY, J., 2004. SIMBA Survey of Southern High-Mass Star Forming Regions. I. Physical Parameters of the 1.2 mm/IRAS Sources. Astron. Astrophys. vol. 426, pp. 97–103. DOI: https://doi.org/10.1051/0004-6361:20035755

59. SCHLINGMAN, W. M., SHIRLEY, Y. L., SCHENK, D. E., ROSOLOWSKY, E., BALLY, J., BATTERSBY, C, DUNHAM, M. K., ELLSWORTH-BOWERS, T. P., EVANCE II, N. J., GINSBURG, A. and STRINGFELLOW, G., 2011. The Bolocam Galactic Plane Survey. V. HCO⁺ and N₂H⁺  Spectroscopy of 1.1 mm Dust Continuum Sources. Astrophys. J. Suppl. Ser. vol. 195, no. 2, id. 14. DOI: https://doi.org/10.1088/0067-0049/195/2/14

60. CYGANOWSKI, C. J., KODA, J., ROSOLOWSKY, E., TOWERS, S., MEYER, J. D., EGUSA, F., MOMOSE, R. and ROBITAILLE, T. P., 2013. A Water Maser and NH3 Survey of GLIMPSE Extended Green Objects. Astrophys. J. vol. 764, no. 1, id. 61. DOI: https://doi.org/10.1088/0004-637X/764/1/61

61. LI, F. C., XU, Y., WU, Y. W., YANG, J., LU, D. R., MENTEN, K. M. and HENKEL, C., 2016. Ammonia and CO Outflow Around 6.7 GHz Methanol Masers. Astron. J. vol. 152, no. 4, id. 92. DOI: https://doi.org/10.3847/0004-6256/152/4/92

62. ZHANG, B., REID, M. J., MENTEN, K. M., ZHENG, X. W., BRUNTHALER, A., DAME, T. M. and XU, Y., 2013. Parallaxes for W49N and G048.60+0.02: Distant Star Forming Regions in the Perseus Spiral Arm. Astrophys. J. vol. 775, no. 1, id. 79. DOI: https://doi.org/10.1088/0004-637X/775/1/79

63. URQUHART, J. S., MOORE, T. J. T., HOARE, M. G., LUMSDEN, S. L., OUDMAIJER, R. D., RATHBORNE, J. M., MOTTRAM, J. C., DAVIES, B. and STEAD, J. J., 2011. The Red MSX Source Survey: Distribution and Properties of a Sample of Massive Young Stars. Mon. Not. R. Astron. Soc. vol. 410, no. 2, pp. 1237–1250. DOI: https://doi.org/10.1111/j.1365-2966.2010.17514.x

64. XU, Y., REID, M. J., MENTEN, K. M., BRUNTHALER, A., ZHENG, X. W. and MOSCADELLI, L., 2009. Trigonometric Parallaxes of Massive Star-Forming Regions: III. G59.7+0.1 and W 51 IRS2. Astrophys. J. vol. 693, pp. 413–418. DOI: https://doi.org/10.1088/0004-637X/693/1/413

65. RUSSEIL, D., 2003. Star-Forming Complexes and the Spiral Structure of Our Galaxy. Astron. Astrophys. vol. 397, no. 1, pp. 133–146. DOI: https://doi.org/10.1051/0004-6361:20021504

66. SLYSH, V. I., VAL'TTS, I. E., KALENSKII, S. V., VORONKOV, M. A., PALAGI, F., TOFANI, G. and CATARZI, M., 1999. The Medicina Survey of Methanol Masers at 6.7 GHz. Astron. Astrophys. Suppl. Ser. vol. 134, no. 1, pp. 115–128. DOI: https://doi.org/10.1051/aas:1999127

67. XU, Y., LI, J. J., REID, M. J., MENTEN, K. M., ZHENG, X. W., BRUNTHALER, A., MOSCADELLI, L., DAME, T. M. and ZHANG, B., 2013. On the Nature of the Local Spiral Arm of the Milky Way. Astrophys. J. vol. 769, no. 1, id. 15. DOI: https://doi.org/10.1088/0004-637X/769/1/15

68. MOSCADELLI, L., CESARONI, R., RIOJA, M. J., DODSON, R. and REID, M. J., 2011. Methanol and Water Masers in IRAS 20126+4104: the Distance, the Disk, and the Jet. Astron. Astrophys. vol. 526, id. A66. DOI: https://doi.org/10.1051/0004-6361/201015641

69. RYGL, K. L. J., BRUNTHALER, A., SANNA, A., MENTEN, K. M., REID, M. J., VAN LANGEVELDE, J. H., HONMA, M., TORSTENSSON, K. J. E. and FUJISAWA, K., 2012. Parallaxes and Proper Motions of Interstellar Masers Toward the Cygnus X Star-Forming Complex. I. Membership of the Cygnus X Region. Astron. Astrophys. vol. 539, id. A79. DOI: https://doi.org/10.1051/0004-6361/201118211

70. WU, Y., WU, J. and WANG, J., 2001. A Search for Massive Dense Cores with ¹³CO  J=1–0 Line. Astron. Astrophys. vol. 380, no. 2, pp. 665–672. DOI: https://doi.org/10.1051/0004-6361:20011498

71. CHOI, Y. K., HACHISUKA, K., REID, M. J., XU, Y., BRUNTHALER, A., MENTEN, K. M. and DAME, T. M., 2014. Trigonometric Parallaxes of Star Forming Regions in the Perseus Spiral Arm. Astrophys. J. vol. 790, no. 2, id. 99. DOI: https://doi.org/10.1088/0004-637X/790/2/99

72. DZIB, S., LOINARD, L., RODRÍGUEZ, L. F., MIODUSZEWSKI, A. J. and TORRES, R. M., 2011. VLBA Determination of the Distance to Nearby Star-Forming Regions. VI. The Distance to the Young Stellar Object HW9 in Cepheus A. Astrophys. J. vol. 733, no. 1, id. 71. DOI: https://doi.org/10.1088/0004-637X/733/1/71

73. MOSCADELLI, L., REID, M. J., MENTEN, K. M., BRUNTHALER, A., ZHENG, X. W. and XU, Y., 2009. Trigonometric Parallaxes of Massive Star-Forming Regions. II. Cep A and NGC 7538. Astrophys. J. vol. 693, no. 1, pp. 406–412. DOI: https://doi.org/10.1088/0004-637X/693/1/406

74. SZYMCZAK, M., BARTKIEWICZ, A. and RICHARDS, A. M. S., 2007. A Multi-Transition Molecular Line Study of Candidate Massive Young Stellar Objects Associated with Methanol Masers. Astron. Astrophys. vol. 468, no. 2, pp. 617–625. DOI: https://doi.org/10.1051/0004-6361:20077289