scholarly journals High angular resolution radio and infrared view of optically dark supernovae in luminous infrared galaxies

2016 ◽  
Vol 12 (S329) ◽  
pp. 332-336
Author(s):  
Seppo Mattila ◽  
Erkki Kankare ◽  
Erik Kool ◽  
Cristina Romero-Cañizales ◽  
Stuart Ryder ◽  
...  
Keyword(s):  
Interstellar Dust ◽  
Angular Resolution ◽  
Formation Rate ◽  
High Angular Resolution ◽  
Infrared Galaxies ◽  
Luminous Infrared Galaxies ◽  
Ultraluminous Infrared Galaxies ◽  
Central Regions ◽  
Nuclear Regions ◽  
The Universe

AbstractIn luminous and ultraluminous infrared galaxies (U/LIRGs), the infall of gas into the central regions strongly enhances the star formation rate (SFR), especially within the nuclear regions which have also large amounts of interstellar dust. Within these regions SFRs of several tens to hundreds of solar masses per year ought to give rise to core-collapse supernova (SN) rates up to 1-2 SNe every year per galaxy. However, the current SN surveys, almost exclusively being ground-based seeing-limited and working at optical wavelengths, have been blinded by the interstellar dust and contrast issues therein. Thus the properties and rates of SNe in the nuclear environments of the most prolific SN factories in the Universe have remained largely unexplored. Here, we present results from high angular resolution observations of nearby LIRGs at infrared and radio wavelengths much less affected by the effects of extinction and lack of resolution hampering the optical searches.

scholarly journals Luminous IR Galaxies: Evolution and Molecular Gas

1997 ◽  
Vol 159 ◽  
pp. 439-440 ◽  
Author(s):  
Yu Gao
Keyword(s):  
Molecular Gas ◽  
Infrared Galaxies ◽  
Galaxy Interactions ◽  
Merging Galaxies ◽  
Star Forming ◽  
Luminous Infrared Galaxies ◽  
Star Forming Regions ◽  
Ir Sources ◽  
Order Of Magnitude ◽  
The Universe

Luminous infrared galaxies (LIRGs), denned by the criterion LIR ≳ 2 × 1011L⊙ (for H0=75 kms−1 Mpc−1), are the most powerful IR sources in the Universe, with most of their emission (~ 90%) in the far-IR. Most LIRGs are interacting/merging galaxies with large amounts of molecular gas as revealed by CO surveys (Sanders et al. 1991; Solomon et al. 1996). However, whether starbursts or dust-enshrouded AGNs/QSOs dominate the IR luminosity is not resolved.CO may not trace the active star-forming regions where gas density is more than one order of magnitude higher than the average. Dense molecular gas is better traced by high dipole-moment molecules like HCN and CS (e.g., Nguyen-Q-Rieu et al. 1992; Gao & Solomon 1996). Therefore, it is essential to survey HCN emission in a large sample of LIRGs to better reveal the nature of LIRGs. We here study IR and molecular gas properties vs. galaxy-galaxy interactions in LIRGs over various merging phases to trace their evolution and explore some links among interactions, starbursts, and AGN phenomena.

Bioenergetics and stellar luminosities

2017 ◽  
Vol 18 (3) ◽  
pp. 211-212
Author(s):  
C Sivaram ◽  
K Arun ◽  
O V Kiren
Keyword(s):  
Metabolic Rate ◽  
Unit Mass ◽  
Infrared Galaxies ◽  
X Ray ◽  
Luminous Infrared Galaxies ◽  
Maximal Metabolic Rate ◽  
Luminous Objects ◽  
The Universe

AbstractWe draw attention to a curious coincidence wherein the most (steadily emitting) luminous objects in the Universe from stellar X-ray sources to ultra-luminous quasars and Ultra Luminous Infrared Galaxies, steadily emit a power per unit mass, which is just the same value as the maximal metabolic rate in (warm-blooded) bio-organisms.

scholarly journals Powerful Molecular Outflows in Nearby Active Galaxies

2013 ◽  
Vol 9 (S304) ◽  
pp. 291-297
Author(s):  
Sylvain Veilleux ◽  
Marcio Meléndez ◽  
Keyword(s):  
Star Formation Rate ◽  
Dominant Role ◽  
Formation Rate ◽  
Wide Angle ◽  
Galaxy Mergers ◽  
Infrared Galaxies ◽  
Molecular Outflows ◽  
Ultraluminous Infrared Galaxies ◽  
Silicate Feature ◽  
Line Widths

AbstractWe report the results from a systematic search for molecular (OH 119 μm) outflows with Herschel-PACS† in a sample of 43 nearby (z < 0.3) galaxy mergers, mostly ultraluminous infrared galaxies (ULIRGs) and QSOs. We find that the character of the OH feature (strength of the absorption relative to the emission) correlates with that of the 9.7-μm silicate feature, a measure of obscuration in ULIRGs. Unambiguous evidence for molecular outflows, based on the detection of OH absorption profiles with median velocities more blueshifted than −50 km s−1, is seen in 26 (70%) of the 37 OH-detected targets, suggesting a wide-angle (~ 145°) outflow geometry. Conversely, unambiguous evidence for molecular inflows, based on the detection of OH absorption profiles with median velocities more redshifted than +50 km s−1, is seen in only 4 objects, suggesting a planar or filamentary geometry for the inflowing gas. Terminal outflow velocities of ~ −1000 km s−1 are measured in several objects, but median outflow velocities are typically ~ −200 km s−1. While the outflow velocities show no statistically significant dependence on the star formation rate, they are distinctly more blueshifted among systems with large AGN fractions and luminosities [log (LAGN/L⊙) ≥ 11.8 ± 0.3]. The quasars in these systems play a dominant role in driving the molecular outflows. In contrast, the most AGN dominated systems, where OH is seen purely in emission, show relatively modest OH line widths, despite their large AGN luminosities, perhaps indicating that molecular outflows subside once the quasar has cleared a path through the obscuring material.

Radioastron: Main results of the implementation of the early science program in studies of astronomical objects in the universe with ultra-high angular resolution

2015 ◽  
Vol 49 (7) ◽  
pp. 573-579 ◽  
Author(s):  
N. S. Kardashev ◽  
A. V. Alakoz ◽  
Y. Y. Kovalev ◽  
M. V. Popov ◽  
A. M. Sobolev ◽  
...  
Keyword(s):  
Angular Resolution ◽  
High Angular Resolution ◽  
Science Program ◽  
The Universe

scholarly journals A Herschel Survey of the [N ii] 205 μm Emission in Local Infrared Luminous Galaxies

2012 ◽  
Vol 8 (S292) ◽  
pp. 256-256
Author(s):  
Yinghe Zhao ◽  
Nanyao Lu ◽  
C. Kevin Xu ◽  
Yu Gao ◽  
Keyword(s):  
Statistical Study ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Line Emission ◽  
Infrared Galaxies ◽  
Star Forming ◽  
Luminous Infrared Galaxies ◽  
High Ionization ◽  
Luminous Galaxies ◽  
Ionization Parameter

AbstractThe [N ii] line is a major coolant in ionized interstellar medium, and is expected to be a good star formation rate indicator. Here we present a statistical study of [N ii] line emission for a large sample of local luminous infrared galaxies (LIRGs) using Herschel SPIRE FTS data (Lu et al. 2012; Zhao et al. 2012, in preparation). For our sample of galaxies, the [N ii] to the total infrared luminosity ratio (L[Nii]/LIR) varies from ∼ 10−5 to ∼ 10−4. We investigate the correlation between L[Nii] and LIR, as well as the dependence of L[Nii]/LIR on LIR, infrared colors (f60/f100) and the OIII 88 μm to [N ii] luminosity ratio. We find that L[Nii] strongly, and almost linearly correlates with LIR for star-forming galaxies, namely log LIR = (4.23 ± 0.33) + (0.99 ± 0.05) log L[NII] (see Fig. 1). The scatter in this relation is mainly due to the variation of hardness, and/or high ionization parameter, of the background UV field.

Hidden Star Formation: The Ultraviolet Perspective

2002 ◽  
Vol 12 ◽  
pp. 489-492 ◽  
Author(s):  
G.R. Meurer ◽  
T.M. Heckman ◽  
M. Seibert ◽  
J. Goldader ◽  
D. Calzetti ◽  
...  
Keyword(s):  
Star Formation ◽  
High Redshift ◽  
Formation Rate ◽  
Flux Ratio ◽  
Far Infrared ◽  
Infrared Galaxies ◽  
Luminous Infrared Galaxies ◽  
Lyman Break Galaxies ◽  
Highly Sensitive ◽  
Dust Absorption

AbstractMany recent estimates of the star formation rate density at high redshift rely on rest-frame ultraviolet (UV) data. These are highly sensitive to dust absorption. Applying a correlation between the far-infrared (FIR) to UV flux ratio and UV color found in local starbursts to galaxy samples out toz∼ 3, one can account for most of the FIR background. However, the correlation is based on a sample that does not include the most extreme starbursts, Ultra Luminous Infrared Galaxies (ULIGs). Our new UV images of ULIGs show that their FIR fluxes are underpredicted by this correlation by factors ranging from 7 to 70. We discuss how ULIGs compare to the various types of high-zgalaxies: sub-mm sources, Lyman Break Galaxies, and Extremely Red Objects.

scholarly journals VLBI from the Moon

1998 ◽  
Vol 11 (2) ◽  
pp. 985-987
Author(s):  
L. I. Gurvits
Keyword(s):  
Radio Astronomy ◽  
Very Long Baseline Interferometry ◽  
Angular Resolution ◽  
High Angular Resolution ◽  
The Moon ◽  
Next Generation ◽  
Space Observatory ◽  
Long Baseline ◽  
The Earth ◽  
The Universe

Very Long Baseline Interferometry (VLBI) technique occupies a special place among tools for studying the Universe due to its record high angular resolution. The latter is in the inverse proportion to the length of interferometer baseline at any given wavelength. Until recently, the available angular resolution in radio domain of about 1 milliarcsecond at centimeter wavelengths was limited by the diameter of the Earth. However, many astrophysical problems require a higher angular resolution. The only way to achieve this at a given wavelength is to create an interferometer with the baseline larger than the Earth’s diameter by placing at least one telescope in space. In February 1997, the first dedicated Space VLBI mission, VLBI Space Observatory Program (VSOP), led by the Institute of Space and Astronautical Sciences (Japan) has been launched (Hirabayashi 1997). The VSOP mission opens a new dimension in the development of radio astronomy of extremely high angular resolution and will be followed by other Space VLBI missions. A review of scientific drives and technological challenges of the next generation Space VLBI mission have been discussed, for example, by Gurvits et al. (1996) and Ulvestad et al. (1997).

scholarly journals AGN and Megamasers

2012 ◽  
Vol 8 (S287) ◽  
pp. 323-332 ◽  
Author(s):  
Andrea Tarchi
Keyword(s):  
Active Galactic Nuclei ◽  
Galactic Nuclei ◽  
Water Molecules ◽  
Host Galaxies ◽  
Infrared Galaxies ◽  
Luminous Infrared Galaxies ◽  
Radio Jets ◽  
Nuclear Regions ◽  
Maser Sources ◽  
Intense Star Formation

AbstractLuminous extragalactic masers are traditionally referred to as the ‘megamasers’. Those produced by water molecules are associated with accretion disks, radio jets, or outflows in the nuclear regions of active galactic nuclei (AGN). The majority of OH maser sources are instead driven by intense star formation in ultra-luminous infrared galaxies, although in a few cases the OH maser emission traces rotating (toroidal or disk) structures around the nuclear engines of AGN. Thus, detailed maser studies provide a fundamental contribution to our knowledge of the main nuclear components of AGN, constitute unique tools to measure geometric distances of host galaxies, and have a great impact on probing the, so far, paradigmatic Unified Model of AGN.

scholarly journals A high-angular resolution study of the nuclear regions of quasar host galaxies with the NaCo simultaneous differential imager

2008 ◽  
Vol 131 ◽  
pp. 012034
Author(s):  
J Scharwächter ◽  
V D Ivanov ◽  
J Zuther ◽  
L E Tacconi-Garman ◽  
J K Kotilainen ◽  
...  
Keyword(s):  
Angular Resolution ◽  
High Angular Resolution ◽  
Host Galaxies ◽  
Nuclear Regions ◽  
Resolution Study

scholarly journals Obscured Supernovae in Starburst Galaxies

2006 ◽  
Vol 2 (S235) ◽  
pp. 323-323 ◽  
Author(s):  
Seppo Mattila ◽  
Peter Meikle ◽  
Robert Greimel ◽  
Petri Väisänen
Keyword(s):  
Starburst Galaxies ◽  
Core Collapse ◽  
Infrared Galaxies ◽  
Dust Extinction ◽  
Core Collapse Supernova ◽  
Luminous Infrared Galaxies ◽  
Near Ir ◽  
Nuclear Regions ◽  
High Dust

About one core-collapse supernova (CCSN) is expected to explode every 5–10 years in the nuclear regions of M 82 and other nearby starburst galaxies. In luminous infrared galaxies (LIRGs) such as the interacting system Arp 299 (NGC 3690 + IC 0694) at least one CCSN can be expected every year. Due to the high dust extinction most of these SNe have remained undetected. Here we show results from two near-IR searches we have recently carried out to detect obscured SNe in nearby starburst galaxies and LIRGs.

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