J/A+A/558/A24 The VLTI/MIDI survey of Massive YSOs (Boley+, 2013)
The VLTI/MIDI survey of massive young stellar objects.
Sounding the inner regions around intermediate- and high-mass young stars using
mid-infrared interferometry.
Boley P.A., Linz H., van Boekel R., Henning T., Feldt M., Kaper L.,
Leinert C., Mueller A., Pascucci I., Roberto M., Stecklum B.,
Waters L.B.F.M., Zinnecker H.
<Astron. Astrophys. 558, A24 (2013)>
=2013A&A...558A..24B 2013A&A...558A..24B
ADC_Keywords: Surveys ; YSOs ; Interferometry
Keywords: surveys - stars: massive - techniques: interferometric
Abstract:
Due to inherent difficulties involved in observations and
theoretical/numerical simulations of the formation of massive stars,
an understanding of the early evolutionary phases of these objects
remains elusive. In particular, observationally probing circumstellar
material at distances ≲100AU from the central star is exceedingly
difficult, as such objects are rare (and thus, on average, far away)
and typically deeply embedded. Long-baseline mid-infrared
interferometry provides one way of obtaining the necessary spatial
resolution at appropriate wavelengths to study this class of objects,
however, interpreting such observations is often difficult due to
sparse spatial-frequency coverage.
We aim to characterize the distribution and composition of
circumstellar material around young massive stars, and to investigate
exactly which physical structures in these objects are probed by
long-baseline mid-infrared interferometric observations.
We use the two-telescope interferometric instrument MIDI of the Very
Large Telescope Interferometer of the European Southern Observatory to
observe a sample of 24 intermediate- and high-mass young stellar
objects in the N band (8-13 micron). We had successful fringe
detections for 20 objects, and present spectrally-resolved correlated
fluxes and visibility levels for projected baselines of up to 128m.
We fit the visibilities with geometric models to derive the sizes of
the emitting regions, as well as the orientation and elongation of the
circumstellar material. A subset of 14 objects show the 10 micron
silicate feature in absorption in the total and correlated flux
spectra. For 13 of these objects, we were able to fit the correlated
flux spectra with a simple absorption model, allowing us to constrain
the composition and absorptive properties of the circumstellar
material.
Description:
We provide the complete set of reduced, spectrally-resolved MIDI
visibilities and differential phases for the 20 objects observed as
part of the survey presented in the above publication. These
interferometric data are provided in FITS format, and, more
specifically, conform to the OIFITS standard (see Pauls et al.,
2005PASP..117.1255P 2005PASP..117.1255P). Additionally, besides the standard OIFITS
columns, the OI_VIS tables in each of the FITS files contain the
columns 'CFLUX' and 'CFLUXERR', which contain the calibrated
correlated flux and its estimated uncertainty (measured in Jy).
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
list.dat 55 20 List of FITS files
fits/* . 20 Individual FITS files in OIFITS format
--------------------------------------------------------------------------------
See also:
J/A+AS/115/285 : Catalogue of massive young stellar objects (Chan+, 1996)
J/A+A/481/345 : SED evolution in massive YSOs (Molinari,+ 2008)
J/ApJ/699/150 : Spectral classifications of massive YSOs in LMC (Seale+, 2009)
Byte-by-byte Description of file: list.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 F9.5 deg RAdeg Right ascension (J2000)
11- 19 F9.5 deg DEdeg Declination (J2000)
21- 22 I2 --- Nuv Number of uv points
24- 39 A16 --- FileName Name of OI-FITS file in subdirectory fits
41- 55 A15 --- Target Target name
--------------------------------------------------------------------------------
Acknowledgements:
Paul Boley, pboley(at)mpifr-bonn.mpg.de
(End) Paul Boley [MPIfR], Patricia Vannier [CDS] 14-Aug-2013