Resolved 24.5 micron emission from massive young stellar objects (2008)
De Wit, W. J., Hoare, M. G., Fujiyoshi, T., Oudmaijer, R. D., Honda, M., Kataza, H., ...
Massive young stellar objects (MYSO) are surrounded by massive dusty envelopes. Our aim is to establish their density structure on scales of ~1000 AU, i.e. a factor 10 increase in angular resolution...
De Wit, W. J., LeBohec, S., Hinton, J. A., White, R. J., Daniel, M. K., Holder, J.
In this poster contribution we highlight the equivalence between an Imaging Air Cherenkov Telescope (IACT) array and an Intensity Interferometer for a range of technical requirements. We touch on the...
A red supergiant nebula at 25 micron: arcsecond scale mass-loss asymmetries of mu Cep (2008)
De Wit, W. J., Oudmaijer, R. D., Fujiyoshi, T., Hoare, M. G., Honda, M., Kataza, H., ...
We present diffraction limited (0.6") 24.5micron Subaru/COMICS images of the red supergiant mu Cep. We report the detection of a circumstellar nebula, that was not detected at shorter wavelengths. It...
Young massive stars and their environment in the mid-infrared at high angular resolution (2008)
De Wit, W. J., Hoare, M. G., Oudmaijer, R. D., Fujiyoshi, T.
We present interferometric and single-dish mid-infrared observations of a sample of massive young stellar objects (BN-type objects), using VLTI-MIDI (10 micron) and Subaru-COMICS (24.5 micron). We...
Detection of the lithium depletion boundary in the young open cluster IC 4665 (2007)
Manzi, S., Randich, S., De Wit, W. J., Palla, F.
The so-called lithium depletion boundary (LDB) provides a secure and independent tool for deriving the ages of young open clusters.In this context, our goal is to determine membership for a sample of...
Resolving the ionized wind of the post-Red Supergiant IRC +10 420 with VLTI/AMBER (2007)
De Wit, W. J., Oudmaijer, R. D., Groenewegen, M. A. T., Hoare, M. G., Malbet, F.
The paper investigates the milli-arcsecond scale structure of the present-day mass-loss of the post-Red Supergiant IRC+10420. We use three telescopes of the VLT Interferometer in combination with the...
VLTI/MIDI 10 micron interferometry of the forming massive star W33A (2007)
De Wit, W. J., Hoare, M. G., Oudmaijer, R. D., Mottram, J. C.
We report on resolved interferometric observations with VLTI/MIDI of the massive young stellar object (MYSO) W33A. The MIDI observations deliver spectrally dispersed visibilities with values between...
Stellar Intensity Interferometry with Air Cherenkov Telescope arrays (2007)
Bohec, S. Le, Daniel, M., De Wit, W. J., Hinton, J. A., Jose, E., Holder, J. A., ...
The present generation of ground-based Very High Energy (VHE) gamma-ray observatories consist of arrays of up to four large (> 12m diameter) light collectors quite similar to those used by R. Hanbury...
The potential for intensity interferometry with gamma-ray telescope arrays (2007)
De Wit, W. J., Bohec, S. Le, Hinton, J. A., White, J., Daniel, M. K., ...
Intensity interferometry exploits a quantum optical effect in order to measure objects with extremely small angular scales. The first experiment to use this technique was the Narrabri intensity...
Small Magellanic Cloud Be stars: colour-magnitude relations and mass-loss (2006)
De Wit, W. J., Marquette, J. B., Beaulieu, J. P.
We present an analysis of optical lightcurves of Small Magellanic Cloud Be-type stars. Observations show that (1) optical excess flux is correlated with near-IR excess flux indicating a similar...
The remarkable light and colour variability of Small Magellanic Cloud Be stars (2006)
De Wit, W. J., Marquette, J. B., Beaulieu, J. P.
(Abridged) Some 240 blue stars in the Small Magellanic Cloud are investigated on their fantastic irregular continuum variability. We report here two results regarding these stars. First, their...
Exploring the Lower Mass Function in the young open Cluster IC 4665 (2005)
De Wit, W. J., Bouvier, J., Palla, F., James, D. J., Kendall, T. R., ...
We present a study of the young (30-100Myr) open cluster IC 4665 with the aim to determine the shape of the mass function well into the brown dwarf regime. We photometrically select 691 low-mass...
Malbet, F., Benisty, M., De Wit, W.J., Kraus, S., Meilland, A., Millour, F., ...
The young stellar object MWC 297 is an embedded B1.5Ve star exhibiting strong hydrogen emission lines and a strong near-infrared continuum excess. This object has been observed with the VLT...
Malbet, F., Benisty, M., De Wit, W.J., Kraus, S., Meilland, A., Millour, F., ...
The young stellar object MWC 297 is an embedded B1.5Ve star exhibiting strong hydrogen emission lines and a strong near-infrared continuum excess. This object has been observed with the VLT...
Malbet, F., Benisty, M., De Wit, W.J., Kraus, S., Meilland, A., Millour, F., ...
The young stellar object MWC 297 is an embedded B1.5Ve star exhibiting strong hydrogen emission lines and a strong near-infrared continuum excess. This object has been observed with the VLT...
Malbet, F., Benisty, M., De Wit, W.J., Kraus, S., Meilland, A., Millour, F., ...
The young stellar object MWC 297 is an embedded B1.5Ve star exhibiting strong hydrogen emission lines and a strong near-infrared continuum excess. This object has been observed with the VLT...
Malbet, F., Benisty, M., De Wit, W. J., Kraus, S., Meilland, A., Millour, F., ...
The young stellar object MWC 297 has been observed with the VLT interferometer equipped with the AMBER instrument. MWC 297 has been spatially resolved in the continuum with a visibility of 0.50 as...
Beaulieu, J. P., De Wit, W. J., Marquette, J. B., Coutures, C., Leisy, P., ...
Using data from the EROS2 microlensing survey, we report the discovery of two blue objects with irregular photometric behaviour of $\\Delta V \\sim 0.1$-0.4 mag on time scales of 20 to 200 days. They...
Malbet, Fabien, Benisty, M., De Wit, W.J., Kraus, S., Meilland, A., Millour, F., ...
The young stellar object MWC297 is a B1.5Ve star exhibiting strong hydrogen emission lines. This object has been observed by the AMBER/VLTI instrument in 2-telescope mode in a sub-region of the K...
Malbet, Fabien, Benisty, M., De Wit, W.J., Kraus, S., Meilland, A., Millour, F., ...
The young stellar object MWC297 is a B1.5Ve star exhibiting strong hydrogen emission lines. This object has been observed by the AMBER/VLTI instrument in 2-telescope mode in a sub-region of the K...
Malbet, Fabien, Benisty, M., De Wit, W. J., Kraus, S., Meilland, A., Millour, F., ...
The young stellar object MWC297 is a B1.5Ve star exhibiting strong hydrogen emission lines. This object has been observed by the AMBER/VLTI instrument in 2-telescope mode in a sub-region of the K...
The Origin of Massive O-type Field Stars. Part II: Field O stars as runaways (2005)
De Wit, W. J., Testi, L., Palla, F., Zinnecker, H.
In two papers we try to confirm that all Galactic high-mass stars are formed in a cluster environment, by excluding that O-type stars found in the Galactic field actually formed there. In de Wit et...
Malbet, Fabien, Benisty, M., De Wit, W.J., Kraus, S., Meilland, A., Millour, F., ...
The young stellar object MWC297 is a B1.5Ve star exhibiting strong hydrogen emission lines. This object has been observed by the AMBER/VLTI instrument in 2-telescope mode in a sub-region of the K...
Malbet, Fabien, Benisty, M., De Wit, W.J., Kraus, S., Meilland, A., Millour, F., ...
The young stellar object MWC297 is a B1.5Ve star exhibiting strong hydrogen emission lines. This object has been observed by the AMBER/VLTI instrument in 2-telescope mode in a sub-region of the K...
The Origin of Massive O-type Field Stars. Part I: A Search for Clusters (2004)
De Wit, W. J., Testi, L., Palla, F., Vanzi, L., Zinnecker, H.
We present a study aimed at clarifying the birthplace for 43 massive O-type field stars. In this first paper we present the observational part: a search for stellar clusters near the target stars. We...
De Wit, W. J., Beaulieu, J-P., Lesquoy, E., Marquette, J-B.
We report the discovery of 5 new Herbig Ae/Be candidate stars in the Small Magellanic Cloud in addition to the 2 reported in Beaulieu et al. (2001). We discuss these 7 HAeBe candidate stars in terms...
VLT/ISAAC H-band spectroscopy of embedded massive YSOs (2003)
Kendall, T. R., De Wit, W. J., Yun, J. L.
We have performed intermediate resolution (R = 5000), high signal-to-noise H-band spectroscopy of a small, initial sample of three massive embedded young stellar objects (YSOs), using VLT/ISAAC. The...
De Wit, W. J., Coutures, C., Leisy, P., ...
Ongoing massive star formation in the bulge of M51 (2001)
Panagia, N., Scuderi, S., Romaniello, M., Spaans, M., De Wit, W. J., ...
We studied the HST-WFPC2 observations of the inner kpc of the interacting galaxy M51 in six bands from 2550 to 8140 Angstrom. The images show an oval shaped area ("bulge") of 11x16 arcsec or 450x650...
Beaulieu, J. P., De Wit, W. J., Marquette, J. B., Coutures, C., Leisy, P., ...
Using data from the EROS2 microlensing survey, we report the discovery of two blue objects with irregular photometric behaviour of $\Delta V \sim 0.1$-0.4 mag on time scales of 20 to 200 days. They...
Beaulieu, J. P., De Wit, W. J., Marquette, J. B., Coutures, C., Leisy, P., ...
Using data from the EROS2 microlensing survey, we report the discovery of two blue objects with irregular photometric behaviour of $\\Delta V \\sim 0.1$-0.4 mag on time scales of 20 to 200 days. They...
De Wit, W. J., Coutures, C., Leisy, P., ...
De Wit, W. J., Coutures, C., Leisy, P., ...
Beaulieu, J. P., De Wit, W. J., Marquette, J. B., Coutures, C., Leisy, P., ...
Using data from the EROS2 microlensing survey, we report the discovery of two blue objects with irregular photometric behaviour of $\\Delta V \\sim 0.1$-0.4 mag on time scales of 20 to 200 days. They...
Some results based on the EROS microlensing survey (1998)
Beaulieu, J. P., De Wit, W. J.
We will review some results based on the EROS and the on going EROS-2 microlensing surveys to search for dark matter in the Galactic halo via microlensing effects on LMC/SMC stars. Microlensing...
The contribution of microlensing surveys to the distance scale (1998)
Beaulieu, J. P., De Wit, W. J.
In the early nineties several teams started large scale systematic surveys of the Magellanic Clouds and the Galactic Bulge to search for microlensing effects. As a by product, these groups have...