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Das M.,Indian Institute of Astrophysics | Saito T.,University of Tokyo | Iono D.,Chile Observatory | Honey M.,Indian Institute of Astrophysics | Ramya S.,Shanghai Astronomical Observatory
Astrophysical Journal | Year: 2015

We present the detection of molecular gas from galaxies located in nearby voids using the CO(1-0) line emission as a tracer. The observations were performed using the 45 m single dish radio telescope of the Nobeyama Radio Observatory. Void galaxies lie in the most underdense parts of our universe and a significant fraction of them are gas rich, late-type spiral galaxies. Although isolated, they have ongoing star formation but appear to be slowly evolving compared to galaxies in denser environments. Not much is known about their star formation properties or cold gas content. In this study, we searched for molecular gas in five void galaxies. The galaxies were selected based on their relatively high IRAS fluxes or Hline luminosities, both of which signify ongoing star formation. All five galaxies appear to be isolated and two lie within the Bootes void. We detected CO(1-0) emission from four of the five galaxies in our sample and their molecular gas masses lie between 108 and 109 Mo. We conducted follow-up Himaging observations of three detected galaxies using the Himalayan Chandra Telescope and determined their star formation rates (SFRs) from their Hfluxes. The SFR varies from 0.2 to 1 Mo yr-1; which is similar to that observed in local galaxies. Our study indicates that although void galaxies reside in underdense regions, their disks contain molecular gas and have SFRs similar to galaxies in denser environments. We discuss the implications of our results. © 2015. The American Astronomical Society. All rights reserved..


Jackson J.M.,Boston University | Rathborne J.M.,CSIRO | Foster J.B.,Yale University | Whitaker J.S.,Boston University | And 62 more authors.
Publications of the Astronomical Society of Australia | Year: 2013

The Millimetre Astronomy Legacy Team 90 GHz (MALT90) survey aims to characterise the physical and chemical evolution of high-mass star-forming clumps. Exploiting the unique broad frequency range and on-the-fly mapping capabilities of the Australia Telescope National Facility Mopra 22 m single-dish telescope 1, MALT90 has obtained 3′ × 3′ maps towards ~2 000 dense molecular clumps identified in the ATLASGAL 870 μm Galactic plane survey. The clumps were selected to host the early stages of high-mass star formation and to span the complete range in their evolutionary states (from prestellar, to protostellar, and on to $\mathrm{H\,{\ scriptstyle {II}}}$ regions and photodissociation regions). Because MALT90 mapped 16 lines simultaneously with excellent spatial (38 arcsec) and spectral (0.11 km s-1) resolution, the data reveal a wealth of information about the clumps' morphologies, chemistry, and kinematics. In this paper we outline the survey strategy, observing mode, data reduction procedure, and highlight some early science results. All MALT90 raw and processed data products are available to the community. With its unprecedented large sample of clumps, MALT90 is the largest survey of its type ever conducted and an excellent resource for identifying interesting candidates for high-resolution studies with ALMA. © 2013 Astronomical Society of Australia.


Niinuma K.,Yamaguchi University | Lee S.-S.,Korea Astronomy and Space Science Institute | Kino M.,Japan Aerospace Exploration Agency | Sohn B.W.,Yamaguchi University | And 68 more authors.
Publications of the Astronomical Society of Japan | Year: 2013

The Korean very-long-baseline interferometry (VLBI) network (KVN) and VLBI Exploration of Radio Astrometry (VERA) Array (KaVA) is the first international VLBI array dedicated to high-frequency (23-43GHz bands) observations in East Asia. Here, we report the first imaging observations of three bright active galactic nuclei (AGNs) known for their complex morphologies: 4C39.25, 3C273, and M87. This is one of the initial results of KaVA's early operation. Our KaVA images reveal extended outflows with complex substructures such as knots and limb brightening, in agreement with previous Very Long Baseline Array (VLBA) observations. Angular resolutions are better than 1.4 and 0.8 mas at 23 and 43GHz, respectively. KaVA achieves a high dynamic range of ∼1000, more than three times the value achieved by VERA. We conclude that KaVA is a powerful array with a great potential for the study of AGN outflows, at least comparable to the best existing radio interferometric arrays. © 2014 © The Author 2014. Published by Oxford University Press on behalf of the Astronomical Society of Japan. All rights reserved.


News Article | February 15, 2017
Site: phys.org

Comet 73P/Schwassmann-Wachmann breaking apart as captured in Slooh's Chile Observatory feed on February 13th, 2017. Credit: Slooh Comet 73P/Schwassmann-Wachmann has experienced a breakup on its journey past the Earth on its way toward the Sun. On the night of February 12th, Slooh members using the company's telescopes in Chile were able to view the comet as it broke into two pieces. This seems to be the continuation of a process that was first witnessed in 1995, then again in 2006. Slooh members were among the first to confirm that the nucleus of comet 73P/Schwassmann-Wachmann had split into at least two large pieces. "They immediately pointed Slooh's telescopes to capture the event," says Slooh Astronomer, Paul Cox. "Members will continue to monitor the comet live over the coming weeks—assuming the comet survives that long." In the coming months—and years—the comet will face its two greatest challenges to survival. First, the Sun. 73P will reach Perihelion, its closest approach to the Sun, on March 16th. "This puts the comet's nucleus under tremendous stress from the Sun's gravitational forces—and it appears that this may have been responsible for carving up the nucleus in two," explains Cox. The question is: will 73P survive perihelion, or will this particular comet be demoted to the annals of astronomical history? If it does, it will have to contend with its second challenge: the gas giant Jupiter. In 2025, 73P will come within 31 million miles of the planet. Jupiter, meanwhile has been known to chew up comets due to its intense gravitational field. "It certainly feels like it's only a matter of time before comet 73P is destroyed, disintegrating into a trail of cosmic dust," Cox continues. This isn't the first time Slooh members have witnessed this kind of cometary activity. In fact, in 2006 they watched amazed as 73P fragmented into at least 30 different pieces as it approached the Sun. It also showed similar signs of breakup in late 1995. According to Slooh astronomers, there are three main drivers for this kind of cometary breakup: Slooh members will be monitoring the comet over the next days and weeks, using both Slooh's Chile and Canary Islands Observatories. Comments Cox, "One thing is certain—if the end-is-nigh for this lump of primordial space rock, Slooh members will be the first to see its demise live in Slooh's telescopes."

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