724 research outputs found
Distances and Kinematics of Gould Belt Star-Forming Regions with Gaia DR2 results
We present an analysis of the astrometric results from Gaia second data
release (DR2) to Young Stellar Objects (YSOs) in star-forming regions related
to the Gould Belt. These regions are Barnard 59, Lupus 1 to 4, Chamaeleon I and
II, -Chamaeleontis, the Cepheus flare, IC 5146 and Corona Australis.
The mean distance to the YSOs in each region are consistent with earlier
estimations, though a significant improvement to the final errors was obtained.
The mean distances to the star-forming regions were used to fit an ellipsoid of
size pc, and centered at
pc, consistent with recently
determined parameter of the Gould Belt. The mean proper motions were combined
with radial velocities from the literature to obtain the three dimensional
motion of the star-forming regions, which are consistent with a general
expansion of the Gould Belt. We estimate that this expansion is occurring at a
velocity of km s. This is the first time that YSOs motions
are used to investigate the kinematic of the Gould Belt. As an interesting side
result, we also identified stars with large peculiar velocities.Comment: 18 pages, 14 figures, and 5 tables. Accepted for publication in The
Astrophysical Journa
Twelfth Intercomparison Campaign of the Regional Brewer Calibration Center Europe: El Arenosillo Atmospheric Sounding Station, Huelva, Spain, 29 May to 9 June 2017
Editado por Alberto Redondas y Stoyka NetchevaThe twelfth European Brewer Intercomparison Campaign was organized by the Regional Brewer Calibration Center for Europe (RBCC-E) in collaboration with the “Area of Instrumentation and Atmospheric Research Area” of Instituto Nacional de Tecnica Aeroespacial (INTA), with the support of the Global Atmosphere Watch (GAW) Programme of the World Meteorological Organization (WMO) and the EUBREWNET ES1207 COST Action. Alongside the campaign, the ATMOZ (Traceability of Atmospheric Total Ozone) project workshop took place at the station. In addition, this event was also used as a demonstration exercise of the calibration methodologies and error assessment developed by the project (Gröbner et al., 2018)
Wavelength calibration of Brewer spectrophotometer using a tunable pulsed laser and implications to the Brewer ozone retrieval
In this contribution we present the wavelength calibration of the travelling reference Brewer spectrometer of the Regional Brewer Calibration Center for Europe (RBCCE) at PTB in Braunschweig, Germany. The wavelength calibration is needed for the calculation of the ozone absorption coefficients used by the Brewer ozone algorithm. In order to validate the standard procedure for determining Brewer’s wavelength scale, a calibration has been performed by using a tunable laser source at PTB in the framework of the EMRP project ENV59 ATMOZ “Traceability for the total column ozone”. Here we compare these results to those of the standard procedure for the wavelength calibration of the Brewer instrument. Such a comparison allows validating the standard methodology used for measuring the ozone absorption coefficient with respect to several assumptions. The results of the laser-based calibrations reproduces those obtained by the standard operational methodology and shows that there is an underestimation of 0.8 % of the ozone absorption coefficients due to the use of the parametrized slit functions.This work has been supported by the European Metrology Research Programme (EMRP) within the joint research project ENV59 “Traceability for atmospheric total column ozone” (ATMOZ). The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union
RBCC-E Triad
Comunicación presentada en: Brewer Ozone Spectrophotometer/Metrology Open Workshop celebrado del 17 al 20 de mayo de 2016 en Ponta Delgada, Azores, Portugal
Brewer-OMI validation
Presentación realizada en: Brewer Ozone Spectrophotometer/Metrology Open Workshop, celebrado en Ponta Delgada (Sao Miguel, Azores) del 17 al 20 de mayo de 2016
The Gould's Belt Very Large Array Survey III. The Orion region
We present results from a high-sensitivity (60 Jy), large-scale (2.26
square degree) survey obtained with the Karl G. Jansky Very Large Array as part
of the Gould's Belt Survey program. We detected 374 and 354 sources at 4.5 and
7.5 GHz, respectively. Of these, 148 are associated with previously known Young
Stellar Objects (YSOs). Another 86 sources previously unclassified at either
optical or infrared wavelengths exhibit radio properties that are consistent
with those of young stars. The overall properties of our sources at radio
wavelengths such as their variability and radio to X-ray luminosity relation
are consistent with previous results from the Gould's Belt Survey. Our
detections provide target lists for followup VLBA radio observations to
determine their distances as YSOs are located in regions of high nebulosity and
extinction, making it difficult to measure optical parallaxes.Comment: Accepted for publication in ApJ; 51 pages, 15 figures, 5 table
Gaia-DR2 confirms VLBA parallaxes in Ophiuchus, Serpens and Aquila
We present Gaia-DR2 astrometry of a sample of YSO candidates in Ophiuchus,
Serpens Main and Serpens South/W40 in the Aquila Rift, which had been mainly
identified by their infrared excess with Spitzer. We compare the Gaia-DR2
parallaxes against published and new parallaxes obtained from our Very Long
Baseline Array (VLBA) program GOBELINS. We obtain consistent results between
Gaia and the VLBA for the mean parallaxes in each of the regions analyzed here.
We see small offsets, when comparing mean values, of a few tens of
micro-arcseconds in the parallaxes, which are either introduced by the Gaia
zero-point error or due to a selection effect by Gaia toward the brightest,
less obscured stars. Gaia-DR2 data alone conclusively places Serpens Main and
Serpens South at the same distance, as we first inferred from VLBA data alone
in a previous publication. Thus, Serpens Main, Serpens South and W40 are all
part of the same complex of molecular clouds, located at a mean distance of
436+/-9 pc. In Ophiuchus, both Gaia and VLBA suggest a small parallax gradient
across the cloud, and the distance changes from 144.2+/-1.3 pc to 138.4+/-2.6
pc when going from L1689 to L1688.Comment: Accepted for publication in ApJ
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