J/A+A/559/L2        H and Ks maps around G045.47+0.05        (Paron+, 2013)

Unveiling the circumstellar environment towards a massive young stellar object. Paron S., Farina C., Ortega E. <Astron. Astrophys. 559, L2 (2013)> =2013A&A...559L...2P 2013A&A...559L...2P
ADC_Keywords: H II regions ; Infrared sources Keywords: stars: formation - ISM: jets and outflows - HII regions Abstract: As a continuation of a previous work, in which we found strong evidence of massive molecular outflows towards a massive star forming site, we present a new study of this region based on very high angular resolution observations with the aim of discovering the outflow driven mechanism. Using near-IR data acquired with Gemini-NIRI at the broad H- and Ks-bands, we study a region of 22"x22" around the UCHII region G045.47+0.05, a massive star forming site at the distance of about 8kpc. To image the source with the highest spatial resolution possible we employed the adaptative optic system ALTAIR, achieving an angular resolution of about 0.15". We discovered a cone-like shape nebula with an opening angle of about 90° extending eastwards the IR source 2MASS J19142564+1109283, a very likely MYSO. This morphology suggests a cavity that was cleared in the circumstellar material and its emission may arise from scattered continuum light, warm dust, and likely emission lines from shock-excited gas. The nebula, presenting arc-like features, is connected with the IR source through a jet-like structure, which is aligned with the blue shifted CO outflow found in a previous study. The near-IR structure lies ∼3" north of the radio continuum emission, revealing that it is not spatially coincident with the UCHII region. The observed morphology and structure of the near-IR nebula strongly suggest the presence of a precessing jet. In this study we have resolved the circumstellar ambient (in scale of a thousand A.U.) of a distant MYSO, indeed one of the farthest cases. File Summary: -------------------------------------------------------------------------------- FileName Lrecl Records Explanations -------------------------------------------------------------------------------- ReadMe 80 . This file list.dat 95 2 List of maps fits/* . 2 Individual maps -------------------------------------------------------------------------------- Byte-by-byte Description of file: list.dat -------------------------------------------------------------------------------- Bytes Format Units Label Explanations -------------------------------------------------------------------------------- 1- 9 F9.5 deg RAdeg Right Ascension of center (J2000) 10- 18 F9.5 deg DEdeg Declination of center (J2000) 20- 25 F6.4 arcsec/pix Scale [0.0217] Scale of the image 27- 30 I4 pix Nx [1024] Number of pixels along X-axis 31 A1 --- --- [x] 32- 35 I4 pix Ny [1024] Number of pixels along Y-axis 37- 46 A10 --- FileName Name of FITS file in subdirectory fits 48- 95 A48 --- Title Title of the file -------------------------------------------------------------------------------- Acknowledgements: Sergio Paron, sparon(at)iafe.uba.ar
(End) Patricia Vannier [CDS] 10-Oct-2013
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