Home ContactSitemap CAS中文
About Us
Brief Introduction
History
Directors
Organization
Research Groups
Scientific Progress
Seminars
Colloquia
CAS Members
Experts
Faculty
Research Fields
Center for Astro-geodynamics
Astrophysics Division
DRAST (Division of Radio Astronomy Science and Technology )
High Technology Laboratories

Location: Home>Research>Seminars
The Herschel/PACS View on the Heating and Cooling of the ISM in local LIRGs
Author:
ArticleSource:
Update time: 2012-09-04
Close
Text Size: A A A
Print
Title: The Herschel/PACS View on the Heating and Cooling of the ISM in local LIRGs
Speaker: Tanio Diaz-Santos (IPAC, Caltech)
Time:  Sept 4 (Tuesday), 2pm
Location: middle conference room

Abstract:
   We present new spectroscopic observations of the main far-infrared (FIR) emission lines detected in a sample of nearby Luminous Infrared Galaxies (LIRGs) using the PACS instrument onboard the Herschel Space Telescope. The Great Observatories All-sky LIRG Survey (GOALS) is a complete, flux-limited galaxy sample that comprises the 202 LIRGs systems (z < 0.088) included in the IRAS Revised Bright Galaxy Sample. The GOALS sample has been observed using Chandra, Galex, HST, Spitzer, and AKARI, among other first-class telescopes. Now, as part of a Herschel Open Time Cycle 1 proposal (PI: L. Armus), we have obtained [CII]158-micron and [OI]63-micron emission line spectroscopy for all GOALS systems as well as [OIII]88-micron spectroscopy for half of the sample. We confirm that LIRGs are a critical galaxy population that bridges the gap between lower luminosity star-forming galaxies showing normal [CII] / L_FIR ratios, and the most IR luminous sources (ULIRGs), which display ratios one order of magnitude smaller -- the so-called far infrared "deficit". We also show that the [CII] / IRAC_8-micron ratio is constant for most of the LIRGs independently of their FIR luminosity, implying that polycyclic aromatic hydrocarbons (PAHs), through the emission of photo-electrons, are the main responsible for the heating of the FIR lines.

Shanghai Astronomical Observatory, All Rights Reserved
80 Nandan Road, Shanghai 200030, China
Tel: +86-21-64386191 Email:shao@shao.ac.cn