Research News

Looking inside the nest: the hidden structure of the merger galaxy Fornax A

posted Sep 25, 2012, 3:15 PM by João Alves   [ updated Sep 26, 2012, 2:27 AM ]

NGC 1316
Deep NTT and VLT observations of merger galaxy NGC 1316 (Fornax A) in one of Yuri Beletsky PhD papers. We find the presence of a structure that resembles inner gaseous spiral arms, at about 5 to 15” from the center (500 to 1500 pc). We also find a disk-like stellar structure with radius less than 200 pc.  

The Orion, Monoceros R2, Rosette, and Canis Major star forming regions

posted Sep 25, 2012, 3:00 PM by João Alves   [ updated Oct 9, 2012, 10:25 AM ]

We converted 19 million stars from the 2MASS database into NICER and NICEST extinction maps of  Orion, Monoceros R2, Rosette, and Canis Major star forming regions, with mean errors of the order of 0.03 mag in Ak. This is an incredible map of an incredible region of the Galaxy, the closest massive star formation region to Earth. Among other things we derived distances via a Galactic model, which are in amazing good agreement with the distances derived in the literature, validating the technique to other more distant regions.   

Deep NIR Survey of the Pipe Nebula II

posted Sep 25, 2012, 2:40 PM by João Alves   [ updated Sep 25, 2012, 2:45 PM ]

Pipe Nebula, NTT-VLT observations
We present a new set of high-resolution dust extinction maps of the nearby and essentially starless Pipe Nebula molecular cloud. We constructed extinction maps from a concerted deep near-infrared imaging survey with the ESO- VLT, ESO-NTT, CAHA 3.5 m telescopes, and 2MASS data. Many results, including the tantalizing clusters of starless cores, in the image above. 

Interview for Servus TV (Hubble - Mission Universum)

posted Sep 28, 2011, 1:32 PM by João Alves   [ updated Sep 29, 2011, 4:07 AM ]

Here is my contribution to the "Hubble - Mission Universum" series by the Austrian TV channel Servus TV. In it I create a star with my bare hands, while discussing my research in star and planet formation. I confess I was impressed by the quality of the series, well done, Servus TV.

Computational Star Formation (Book)

posted Sep 22, 2011, 4:53 AM by João Alves

The rapid advance of computer capabilities over the last two decades has opened up a new field of numerical simulations in which detailed physical models can be made to represent the most complex processes. "Computational Star Formation" reviews the latest techniques and results of numerical simulations relevant to interstellar gas dynamics and star formation. Topics range from dynamics to radiation and visualization, as applied to both local and cosmological problems. This book is ideal for graduate students and researchers in numerical astrophysics. It's really good. Buy it here! 

Grabing the Bull by its tail (Star Formation in the Taurus Filament)

posted Jan 31, 2011, 2:22 AM by João Alves

Deep extinction mapping of the Taurus filament with the Calar Alto 3.5m telescope. The filament is more fragmented that originally thought and has a high mass-per-length value of M line = 17M sun pc-1, making it star formation prone. The dense core mass function is similar to the one in the Pipe Nebula (Alves et al. 2007), in case you were wondering. Congratulations to Markus Schmalz for leading this effort successfully. 

VLT-MAD observations of the core of 30 Doradus

posted Jan 26, 2011, 12:04 PM by João Alves

The next generation of large telescopes will need Multiconjugate Adaptive Optics. But will this new technique work? 30 Dor is one of the regions that always reminds me of how little we know about star formation. It is an impressive star factory, unlike any of our Milkyway, and it is also the perfect target to test Multiconjugate Adaptive optics Demonstrator (MAD) at the Very Large Telescope, with the Near-Infrared camera CAMCAO. The technique works, and the paper presenting first results, that contradict results from optical wavelengths, is here

On the Star Formation Rates in Molecular Clouds

posted Jan 26, 2011, 11:07 AM by João Alves   [ updated Apr 26, 2011, 2:56 PM ]

Both the yield and rate of star formation can vary considerably in clouds, independent of their mass and size, but above a certain threshold in column density clouds become predictable. In this paper we find that the star formation rate is proportional to the cloud mass above an extinction threshold of AK ≈ 0.8 mag, corresponding to a gas surface density threshold of Σgas ≈ 116M pc2. (or volume densities about 104 cm-3). In other words, once you have dense gas you have stars. The more dense gas you have, the more the stars you'll produce. Understanding star formation is understanding how nature transforms diffuse gas into dense gas. Easy. 

Larson's third law and the universality of molecular cloud structure

posted Sep 30, 2010, 8:43 AM by João Alves   [ updated Apr 26, 2011, 2:56 PM ]

There is something funny about dark clouds. They have terrible complicated geometries, a wide range of evolutionary status and star formation histories, but yet they all seem to have the basic underlying structure. Why? And what are the log-normals hiding? 

The Taurus, Perseus, and California cloud complexes

posted Sep 30, 2010, 8:07 AM by João Alves   [ updated Apr 26, 2011, 2:55 PM ]

This is paper III of the 2MASS wide field extinction maps series, this time mapping of a large region in the sky (~ 3500 deg2) towards the directions of Taurus, Perseus, and Aries. The map was constructed with the colors of ~23 million stars. We find a ~ 25° × 15° region close to the galactic plane (l ~ 135°, b ~ -14°) with small extinction (AK < 0.04 mag); we name this region the Perseus-Andromeda hole.  The maps have an amazing wealth of new information on molecular cloud structure, and are just gorgeous to look at.

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