158 research outputs found
Dusty Universe viewed by AKARI far infrared detector
We present the results of the analysis of multiwavelength Spectral Energy
Distributions (SEDs) of far-infrared galaxies detected in the AKARI Deep
Field-South (ADF--S) Survey. The analysis uses a carefully selected sample of
186 sources detected at the 90 m AKARI band, identified as galaxies with
cross-identification in public catalogues. For sources without known
spectroscopic redshifts, we estimate photometric redshifts after a test of two
independent methods: one based on using mainly the optical -- mid infrared
range, and one based on the whole range of ultraviolet -- far infrared data. We
observe a vast improvement in the estimation of photometric redshifts when far
infrared data are included, compared with an approach based mainly on the
optical -- mid infrared range. We discuss the physical properties of our
far-infrared-selected sample. We conclude that this sample consists mostly of
rich in dust and young stars nearby galaxies, and, furthermore, that almost 25%
of these sources are (Ultra)Luminous Infrared Galaxies. Average SEDs normalized
at 90 m for normal galaxies (138 sources), LIRGs (30 sources), and ULIRGs
(18 galaxies) a the significant shift in the peak wavelength of the dust
emission, and an increasing ratio between their bolometric and dust
luminosities which varies from 0.39 to 0.73.Comment: 8 pages, 7 figures, published in Earth, Planets and Spac
AKARI/IRC Broadband Mid-infrared data as an indicator of Star Formation Rate
AKARI/Infrared Camera (IRC) Point Source Catalog provides a large amount of
flux data at {\it S9W} () and {\it L18W} ()
bands. With the goal of constructing Star-Formation Rate(SFR) calculations
using IRC data, we analyzed an IR selected
GALEX-SDSS-2MASS-AKARI(IRC/Far-Infrared Surveyor) sample of 153 nearby
galaxies. The far-infrared fluxes were obtained from AKARI diffuse maps to
correct the underestimation for extended sources raised by the point-spread
function photometry. SFRs of these galaxies were derived by the spectral energy
distribution fitting program CIGALE. In spite of complicated features contained
in these bands, both the {\it S9W} and {\it L18W} emission correlate with the
SFR of galaxies. The SFR calibrations using {\it S9W} and {\it L18W} are
presented for the first time. These calibrations agree well with previous works
based on Spitzer data within the scatters, and should be applicable to
dust-rich galaxies.Comment: PASJ, in pres
Functionalized nanoporous gold as a new biosensor platform for ultra-low quantitative detection of human serum albumin
A broad-selective enzyme immunoassay for non-invasive stress assessment in African Penguins 1 (Spheniscus demersus) held in captivity
The infrared emission of ultraviolet selected galaxies from z = 0 to z=1
We select galaxies in UV rest-frame at z=0, z~0.7 and z~1 together with a
sample of LBGs at z~1, the samples are built in order to sample the same range
of luminosity at any redshift. The evolution of the IR and UV luminosities with
z is analysed for individual galaxies as well as in terms of luminosity
functions. The L_IR/L_UV ratio is used to measure dust attenuation. This ratio
does not exhibit a strong evolution with z for the bulk of our sample galaxies
but some trends are found for galaxies with a strong dust attenuation and for
UV luminous sources: galaxies with L_IR/L_UV>10 are more frequent at z>0 than
at z=0 and the largest values of L_IR/L_UV are found for UV faint objects;
conversely the most luminous galaxies of our samples (L_UV> 2 10^{10} L_sun$),
detected at z=1, exhibit a lower dust attenuation than the fainter ones.
L_IR/L_UV increases with the K rest-frame luminosity of the galaxies at all the
redshifts considered and shows a residual anti-correlation with L_UV. The most
massive and UV luminous galaxies exhibit quite large specific star formation
rates. LBGs exhibit systematically lower dust attenuation than UV selected
galaxies of same luminosity but similar specific star formation rates. The
analysis of the UV+IR luminosity functions leads to the conclusion that up to z
= 1 most of the star formation activity of UV selected galaxies is emitted in
IR. Whereas we are able to retrieve all the star formation from our UV
selection at z=0.7, at z = 1 we miss a large fraction of galaxies more luminous
than ~ 10^{11} L_sun. The effect is found larger for Lyman Break Galaxies.Comment: 13 pages. accepted for publication (Astronomy and Astrophysics
Lamin A/C truncation in dilated cardiomyopathy with conduction disease
BACKGROUND: Mutations in the gene encoding the nuclear membrane protein lamin A/C have been associated with at least 7 distinct diseases including autosomal dominant dilated cardiomyopathy with conduction system disease, autosomal dominant and recessive Emery Dreifuss Muscular Dystrophy, limb girdle muscular dystrophy type 1B, autosomal recessive type 2 Charcot Marie Tooth, mandibuloacral dysplasia, familial partial lipodystrophy and Hutchinson-Gilford progeria. METHODS: We used mutation detection to evaluate the lamin A/C gene in a 45 year-old woman with familial dilated cardiomyopathy and conduction system disease whose family has been well characterized for this phenotype [1]. RESULTS: DNA from the proband was analyzed, and a novel 2 base-pair deletion c.908_909delCT in LMNA was identified. CONCLUSIONS: Mutations in the gene encoding lamin A/C can lead to significant cardiac conduction system disease that can be successfully treated with pacemakers and/or defibrillators. Genetic screening can help assess risk for arrhythmia and need for device implantation
Active Disk Building in a local HI-Massive LIRG: The Synergy between Gas, Dust, and Star Formation
HIZOA J0836-43 is the most HI-massive (M_HI = 7.5x10^10 Msun) galaxy detected
in the HIPASS volume and lies optically hidden behind the Milky Way. Markedly
different from other extreme HI disks in the local universe, it is a luminous
infrared galaxy (LIRG) with an actively star forming disk (>50 kpc), central to
its ~ 130 kpc gas disk, with a total star formation rate (SFR) of ~20.5 Msun
yr^{-1}. Spitzer spectroscopy reveals an unusual combination of powerful
polycyclic aromatic hydrocarbon (PAH) emission coupled to a relatively weak
warm dust continuum, suggesting photodissociation region (PDR)-dominated
emission. Compared to a typical LIRG with similar total infrared luminosity
(L_TIR=10^11 Lsun), the PAHs in HIZOA J0836-43 are more than twice as strong,
whereas the warm dust continuum (lambda > 20micron) is best fit by a star
forming galaxy with L_TIR=10^10 Lsun. Mopra CO observations suggest an extended
molecular gas component (H_2 + He > 3.7x10^9 Msun) and a lower limit of ~ 64%
for the gas mass fraction; this is above average compared to local disk
systems, but similar to that of z~1.5 BzK galaxies (~57%). However, the star
formation efficiency (SFE = L_IR/L'_CO) for HIZOA J0836-43 of 140 Lsun (K km
s^{-1} pc^2)^{-1} is similar to that of local spirals and other disk galaxies
at high redshift, in strong contrast to the increased SFE seen in merging and
strongly interacting systems. HIZOA J0836-43 is actively forming stars and
building a massive stellar disk. Its evolutionary phase of star formation
(M_stellar, SFR, gas fraction) compared to more distant systems suggests that
it would be considered typical at redshift z~1. This galaxy provides a rare
opportunity in the nearby universe for studying (at z~0.036) how disks were
building and galaxies evolving at z~1, when similarly large gas fractions were
likely more common.Comment: Accepted for publication in The Astrophysical Journal. 16 pages, 8
figure
Star formation and dust extinction properties of local galaxies from AKARI-GALEX All-Sky Surveys: First results from most secure multiband sample from FUV to FIR
The AKARI All-Sky Survey provided the first bright point source catalog
detected at 90um. Starting from this catalog, we selected galaxies by matching
AKARI sources with those in the IRAS PSCz. Next, we have measured total GALEX
FUV and NUV flux densities. Then, we have matched this sample with SDSS and
2MASS galaxies. By this procedure, we obtained the final sample which consists
of 607 galaxies. If we sort the sample with respect to 90um, their average SED
shows a coherent trend: the more luminous at 90um, the redder the global SED
becomes. The M_r--NUV-r color-magnitude relation of our sample does not show
bimodality, and the distribution is centered on the green valley between the
blue cloud and red sequence seen in optical surveys. We have established
formulae to convert FIR luminosity from AKARI bands to the total infrared (IR)
luminosity L_TIR. With these formulae, we calculated the star formation
directly visible with FUV and hidden by dust. The luminosity related to star
formation activity (L_SF) is dominated by L_TIR even if we take into account
the far-infrared (FIR) emission from dust heated by old stars. At high star
formation rate (SFR) (> 20 Msun yr^-1), the fraction of directly visible SFR,
SFR_FUV, decreases. We also estimated the FUV attenuation A_FUV from
FUV-to-total IR (TIR) luminosity ratio. We also examined the L_TIR/L_FUV-UV
slope (FUV- NUV) relation. The majority of the sample has L_TIR/L_FUV ratios 5
to 10 times lower than expected from the local starburst relation, while some
LIRGs and all the ULIRGs of this sample have higher L_TIR/L_FUV ratios. We
found that the attenuation indicator L_TIR/L_FUV is correlated to the stellar
mass of galaxies, M*, but there is no correlation with specific SFR (SSFR),
SFR/M*, and dust attenuation L_TIR/L_FUV. (abridged)Comment: 13 pages, 18 figures, accepted for publication in A&
Analysis of galaxy SEDs from far-UV to far-IR with CIGALE: Studying a SINGS test sample
Photometric data of galaxies covering the rest-frame wavelength range from
far-UV to far-IR make it possible to derive galaxy properties with a high
reliability by fitting the attenuated stellar emission and the related dust
emission at the same time. For this purpose we wrote the code CIGALE (Code
Investigating GALaxy Emission) that uses model spectra composed of the Maraston
(or PEGASE) stellar population models, synthetic attenuation functions based on
a modified Calzetti law, spectral line templates, the Dale & Helou dust
emission models, and optional spectral templates of obscured AGN. Depending on
the input redshifts, filter fluxes are computed for the model set and compared
to the galaxy photometry by carrying out a Bayesian-like analysis. CIGALE was
tested by analysing 39 nearby galaxies selected from SINGS. The reliability of
the different model parameters was evaluated by studying the resulting
expectation values and their standard deviations in relation to the input model
grid. Moreover, the influence of the filter set and the quality of photometric
data on the code results was estimated. For up to 17 filters between 0.15 and
160 mum, we find robust results for the mass, star formation rate, effective
age of the stellar population at 4000 A, bolometric luminosity, luminosity
absorbed by dust, and attenuation in the far-UV. A study of the mutual
relations between the reliable properties confirms the dependence of star
formation activity on morphology in the local Universe and indicates a
significant drop in this activity at about 10^11 M_sol towards higher total
stellar masses. The dustiest sample galaxies are present in the same mass
range. [abridged]Comment: 22 pages, 21 figures, accepted for publication in A&
The Herschel Multi-tiered Extragalactic Survey: HerMES
The Herschel Multi-tiered Extragalactic Survey, HerMES, is a legacy program
designed to map a set of nested fields totalling ~380 deg^2. Fields range in
size from 0.01 to ~20 deg^2, using Herschel-SPIRE (at 250, 350 and 500 \mu m),
and Herschel-PACS (at 100 and 160 \mu m), with an additional wider component of
270 deg^2 with SPIRE alone. These bands cover the peak of the redshifted
thermal spectral energy distribution from interstellar dust and thus capture
the re-processed optical and ultra-violet radiation from star formation that
has been absorbed by dust, and are critical for forming a complete
multi-wavelength understanding of galaxy formation and evolution.
The survey will detect of order 100,000 galaxies at 5\sigma in some of the
best studied fields in the sky. Additionally, HerMES is closely coordinated
with the PACS Evolutionary Probe survey. Making maximum use of the full
spectrum of ancillary data, from radio to X-ray wavelengths, it is designed to:
facilitate redshift determination; rapidly identify unusual objects; and
understand the relationships between thermal emission from dust and other
processes. Scientific questions HerMES will be used to answer include: the
total infrared emission of galaxies; the evolution of the luminosity function;
the clustering properties of dusty galaxies; and the properties of populations
of galaxies which lie below the confusion limit through lensing and statistical
techniques.
This paper defines the survey observations and data products, outlines the
primary scientific goals of the HerMES team, and reviews some of the early
results.Comment: 23 pages, 17 figures, 9 Tables, MNRAS accepte
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