14
Jan 10

The quest for Extragalactic Exoplanets begins...

Source: arXiv:1001.2105v1

While the most distant exoplanets detected until today are OGLE-05-390L b, MOA-2007-BLG-400-L b at around 6,500 & 6,000 parsecs, which  roughly means ~21,190 & ~19,500 light-years away respectively, an international team of astronomers proposes  a new observational method that they believe will allow  the detection of exoplanets in the Andromeda galaxy (M31) that is at a distance of 2.9 million light-years from us.


A simulation of the expected microlensing event. Credit: Ingrosso et al. (2009)

The authors think that that exoplanets in the M31 galaxy may be detected with the pixel-lensing method by using telescopes making high cadence observations of an ongoing microlensing event.Although the mean mass for detectable exoplanets is about 2 MJ, even small mass exoplanets (inferior to 20 Earth masses) can cause significant deviations, which are observable with large telescopes. (read more)

Link:

Ingrosso,G., De Paolis,F., Novati,S.C., Jetzer,Ph.,  Nucita,A.A., Zakharov,A. F. (2009). Detection of Exoplanets in M31 with Pixel-Lensing: The Event Pa-99-N2 Case, in proceedings of the "Twelfth Marcel Grosmann Meeting", Paris.

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14
Jan 10

Celebrating the fifth anniversary of Huygens' Titan touchdown

Source: ESA General


Composite of Huygens DISR images shows patterns of drainage, flow and erosion in the Huygens landing site region. Credits: ESA/NASA/JPL/University of Arizona

Five years ago today, ESA's Huygens probe descended to the surface of Titan, Saturn's largest moon. Today planetary scientists from around the world have gathered in Barcelona to discuss the legacy of Huygens and to consider future Titan exploration missions.(read more)

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14
Jan 10

Finding Galaxy Clusters at redshift ~1.8

Source: arXiv:1001.2232v1


RGB “color” images of one of the three candidate clusters around COSMOS-FR I 03 . The image was obtained using Spitzer 3.6μm, Subaru r and B band images for the R, G and B channels respectively. White circles indicate objects with 1.6 < zphot < 2.3. The projected size of the fields are 18000 × 18000 (~ 1.5 × 1.5 Mpc2 at z ~ 1.8), North is up.
Credit: COSMOS team.

A team of astronomers from several organizations presented three candidate clusters of galaxies at redshifts between 1.7 and 2.0, which corresponds to a fundamentally unexplored epoch of clusters evolution. The candidates were found by studying the environment around our newly selected sample of “beacons” low-luminosity (FR I) radio galaxies. Detection of galaxy clusters from this epoch doesn't have a completely convincing method and the search for clusters of galaxies at z > 1 has proven to be particularly difficult, mainly because of the reduced contrast between cluster members and field galaxies.

The team has now proposed a method that seems suitable to make detections of these galaxy clusters. (read more)

The article in arXiv:
Chiaberge, M., Capetti,A., Macchetto,D., Rosati,P., Tozzi, P., Tremblay,P.R. (2010).Three candidate clusters of galaxies at redshift ~1.8: The missing link between protoclusters and local clusters?,Accepted for publication in ApJL.

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14
Jan 10

Asteroid 2010 AL30 passes close to Earth

Source: Space Weather

Is it an asteroid or a derelict spacecraft? Mystery object 2010 AL30 is flew past Earth last night only 1/3rd the distance to the Moon, and telescopes around the world were watching.


2010 AL30 is the faint object that comes down to the right.
This image was made in Colombia, using a 14-inch Meade LX200.
Credit: Alberto Quijano Vodniza (Amateur Astronomer)

Potentially Hazardous Asteroids (PHAs) are space rocks larger than approximately 100m that can come closer to Earth than 0.05 AU. None of the known PHAs is on a collision course with our planet, although astronomers are finding new ones all the time.

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14
Jan 10

Formation of Dwarf Galaxies explained

Source: University of Washington


These images depict various stages of galaxy formation under the cold dark
matter theory using new computer simulations that account for the effects
of supernova explosions. Credit: Katy Brooks

For more than two decades, the cold dark matter theory has been used by cosmologists to explain how the smooth universe born in the big bang more than 13 billion years ago evolved into the filamentary, galaxy-rich cosmic web that we see today.

There's been just one problem: The theory suggested most galaxies should have far more stars and dark matter at their cores than they actually do. The problem is most pronounced for dwarf galaxies, the most common galaxies in our own celestial neighborhood. Each contains less than 1 percent of the stars found in large galaxies such as the Milky Way.

Now an international research team, led by a UW astronomer, reports in the Jan. 14 issue of Nature that it resolved the problem using millions of hours on supercomputers to run simulations of galaxy formation (1 million hours is more than 100 years). The simulations produced dwarf galaxies very much like those observed today by satellites and large telescopes around the world. (read more)

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14
Jan 10

UI astronomers capture first-of-kind image at distant star

Source: University of Iowa

Image: Composite image of a large radio coronal loop superimposed on an artist's conception of Algol, a binary star system. Credit: William Peterson.

Two University of Iowa researchers have made the first direct radio image of a coronal loop at a star, other than the sun, thereby providing scientists with information that may lead to a better understanding of how such phenomena as space weather affect the Earth. (read more)

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