114 research outputs found
Far-Infrared Emission from Dust in the ISOPHOT Virgo Cluster Deep Sample
We review the characteristics of the dust continuum emission from normal
galaxies, as revealed by the ISOPHOT Virgo Cluster Deep Survey (Tuffs et al.
2002; Popescu et al. 2002, Popescu & Tuffs 2002b).Comment: 5 pages (Latex), 4 included figures (eps and ps); selected topics
from the invited talk held at the Ringberg Workshop on the Virgo Cluster,
14-17 June 200
Modelling the spectral energy distribution of galaxies from the ultraviolet to submillimeter
We present results from a new modelling technique which can account for the
observed optical/NIR - FIR/submm spectral energy distributions (SEDs) of normal
star-forming galaxies in terms of a minimum number of essential parameters
specifying the star-formation history and geometrical distribution of stars and
dust. The model utilises resolved optical/NIR images to constrain the old
stellar population and associated dust, and geometry-sensitive colour
information in the FIR/submm to constrain the spatial distributions of young
stars and associated dust. It is successfully applied to the edge-on spirals
NGC891 and NGC5907. In both cases the young stellar population powers the bulk
of the FIR/sub-mm emission. The model also accounts for the observed surface
brightness distribution and large-scale radial brightness profiles in NGC891 as
determined using the Infrared Space Observatory (ISO) at 170 and 200 mcrions
and at 850 micron using SCUBA.Comment: 20 pages (Latex), Highlight talk at the Joint European and National
Astronomical Meeting JENAM 2001, to be published in Reviews in Modern
Astronomy 15: Five Days of Creation: Astronomy with Large Telescopes from
Ground and Base. Germany : Astronomische Gesellschaft, 200
Normal Nearby Galaxies
Following on from IRAS, ISO has provided a huge advancement in our knowledge
of the phenomenology of the infrared (IR) emission of normal galaxies and the
underlying physical processes. Highlights include: the discovery of an extended
cold dust emission component, present in all types of gas-rich galaxies and
carrying the bulk of the dust luminosity; the definitive characterisation of
the spectral energy distribution in the IR, revealing the channels through
which stars power the IR light; the derivation of realistic geometries for
stars and dust from ISO imaging; the discovery of cold dust associated with HI
extending beyond the optical body of galaxies; the remarkable similarity of the
near-IR (NIR)/ mid-IR (MIR) SEDs for spiral galaxies, revealing the importance
of the photo-dissociation regions in the energy budget for that wavelength
range; the importance of the emission from the central regions in shaping up
the intensity and the colour of the global MIR luminosity; the discovery of the
``hot'' NIR continuum emission component of interstellar dust; the predominance
of the diffuse cold neutral medium as the origin for the main interstellar
cooling line, [CII] 158 micron, in normal galaxies.Comment: 47 pages, 15 figures, to be published in the ISO Special Issue of
Space Science Reviews: "ISO science legacy - a compact review of ISO major
achievements", Springer 2005. See http://www.iso.vilspa.esa.es/science/SSR/
for a higher resolution version and for all papers in the volum
Dust effects on the derived Sersic indexes of disks and bulges in spiral galaxies
We present a theoretical study that quantifies the effect of dust on the
derived Sersic indexes of disks and bulges. The changes in the derived
parameters from their intrinsic values (as seen in the absence of dust) were
obtained by fitting Sersic distributions on simulated images of disks and
bulges produced using radiative transfer calculations and the model of Popescu
et al. 2011. We found that dust has the effect of lowering the measured Sersic
index in most cases, with stronger effects for disks and bulges seen through
more optically thick lines of sight.Comment: 3 pages, 2 figures, to appear in the Proceedings of the IAU Symposium
No.284, "The Spectral Energy Distribution of Galaxies", 5-9 sept. 2011,
editors Richard J. Tuffs and Cristina C. Popesc
Normal Gas-Rich Galaxies in the Far-Infrared: The Legacy of ISOPHOT
Following on from IRAS, the ISOPHOT instrument on board the Infrared Space
Observatory (ISO) has provided a huge advancement in our knowledge of the
phenomenology of the far-infrared (FIR) emission of normal galaxies and the
underlying physical processes. Highlights include: the discovery of an extended
cold dust emission component, present in all types of gas-rich galaxies and
carrying the bulk of the dust luminosity; the definitive characterisation of
the spectral energy distribution in the FIR, revealing the channels through
which stars power the FIR light; the derivation of realistic geometries for
stars and dust from ISOPHOT imaging and the discovery of cold dust associated
with HI extending beyond the optical body of galaxies.Comment: Invited review presented at "The Spectral Energy Distribution of
Gas-Rich Galaxies: Confronting Models with Data", Heidelberg, 4-8 Oct. 2004
(to be published in AIP Conf. Ser.); for a version with full resolution
figures go to http://edoc.mpg.de/207563.
Far-infrared Emission from Dust in Normal Galaxies
We review the morphological and spectral energy distribution characteristics
of the dust continuum emission (emitted in the 40-200 micron spectral range)
from normal galaxies, as revealed by detailed ISOPHOT mapping observations of
nearby spirals and by ISOPHOT observations of the integrated emissions from
representative statistical samples in the local universe.Comment: 7 pages with 5 figures included (eps format); invited review talk
held at the ESA Workshop ``Exploiting the ISO Data Archive. Infrared
Astronomy in the Internet Age'', Siguenza, Spain 24-27 June, 200
Starburst in the Intragroup Medium of Stephan's Quintet
Based on new ISO mid-infrared observations and ground based and
near-infrared observations, we report the detection of a bright starburst in
the intragroup medium (IGM) of the famous compact group of galaxies Stephan's
Quintet (Source A in Fig.1). We demonstrate that this starburst is caused by a
collision between a high velocity (V 1000 km/sec) intruder galaxy
(NGC7318b) and the IGM of the group. While this is the only starburst known
today that is induced by a galaxy/cold-intergalactic-medium collision, it
provides new constraints to the theory for interaction-induced starbursts, and
may hint at a new mechanism for the star formation excess seen in more distant
clusters.Comment: 17 pages, 2 PS figures. Accepted by Ap
The percentage of stellar light re-radiated by dust in late-type Virgo Cluster galaxies
We show that the mean percentage of stellar light re-radiated by dust is ~30
percent for the Virgo Cluster late-spirals measured with ISOPHOT by Tuffs et
al. (2002). A strong dependence of this ratio with morphological type was
found, ranging from typical values of ~15 percent for early spirals to up to
~50 percent for some late spirals. The extreme BCDs can have even higher
percentages of their bolometric output re-radiated in the thermal infrared.
Luminosity correction factors for the cold dust component are given for general
use in converting far-infrared (FIR) luminosities derived from IRAS.Comment: 5 pages, 3 eps figures, accepted for publication in MNRAS Letter
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