Unbiased Large Spectroscopic Surveys of Galaxies Selected by SPICA Using Dust Bands

AbstractThe mid-infrared range contains many spectral features associated with large molecules and dust grains such as polycyclic aromatic hydrocarbons and silicates. These are usually very strong compared to fine-structure gas lines, and thus valuable in studying the spectral properties of faint distant galaxies. In this paper, we evaluate the capability of low-resolution mid-infrared spectroscopic surveys of galaxies that could be performed by SPICA. The surveys are designed to address the question how star formation and black hole accretion activities evolved over cosmic time through spectral diagnostics of the physical conditions of the interstellar/circumnuclear media in galaxies. On the basis of results obtained with Herschel far-infrared photometric surveys of distant galaxies and Spitzer and AKARI near- to mid-infrared spectroscopic observations of nearby galaxies, we estimate the numbers of the galaxies at redshift z > 0.5, which are expected to be detected in the polycyclic aromatic hydrocarbon features or dust continuum by a wide (10 deg2) or deep (1 deg2) blind survey, both for a given observation time of 600 h. As by-products of the wide blind survey, we also expect to detect debris disks, through the mid-infrared excess above the photospheric emission of nearby main-sequence stars, and we estimate their number. We demonstrate that the SPICA mid-infrared surveys will efficiently provide us with unprecedentedly large spectral samples, which can be studied further in the far-infrared with SPICA.

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PAH features in Infrared Luminous Galaxies: Results from Michelle

Symposium - International Astronomical Union ◽

10.1017/s0074180900197554 ◽

2004 ◽

Vol 217 ◽

pp. 216-217

Author(s):

M. S. Clemens ◽

B. Nikolic ◽

P. Alexander ◽

G. Cotter ◽

M. S. Longair

Keyword(s):

Narrow Band Imaging ◽

Far Infrared ◽

Infrared Emission ◽

Radio Continuum ◽

Energy Output ◽

Mid Infrared ◽

Infrared Observations ◽

Relative Contribution ◽

Polycyclic Aromatic ◽

Continuum Data

We present recent results from mid-infrared observations of a sample of nearby, infrared luminous starbursts and AGN made with the new mid-infrared instrument, “Michelle”, on UKIRT. Narrow band imaging in the 7-13 micron range with sub-arcsec resolution has been used to study the spatial distribution of polycyclic aromatic hydrocarbon (PAH) features. The comparison of these sub-arcsecond resolution data with radio continuum data at similar resolution can be used to determine, 1) the sources of excitation required for PAH emission, and 2) whether PAH features are a measure of the relative contribution of star formation and AGN to the bolometric energy output of a galaxy. Unlike the far-infrared emission from dust, that in the mid-infrared can be used to discriminate between different heating sources.

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Analysing the spectral energy distributions of Galactic classical Cepheids

Astronomy and Astrophysics ◽

10.1051/0004-6361/201937060 ◽

2020 ◽

Vol 635 ◽

pp. A33 ◽

Cited By ~ 2

Author(s):

M. A. T. Groenewegen

Keyword(s):

Near Infrared ◽

Three Dimensional ◽

Far Infrared ◽

Spectral Energy ◽

Spectral Energy Distributions ◽

Instability Strip ◽

Energy Distributions ◽

Infrared Excess ◽

Mid Infrared ◽

Classical Cepheids

Spectral energy distributions (SEDs) were constructed for a sample of 477 classical Cepheids (CCs); including stars that have been classified in the literature as such but are probably not. The SEDs were fitted with a dust radiative transfer code. Four stars showed a large mid- or far-infrared excess and the fitting then included a dust component. These comprise the well-known case of RS Pup, and three stars that are (likely) Type-II Cepheids (T2Cs), AU Peg, QQ Per, and FQ Lac. The infrared excess in FQ Lac is reported for the first time in this work. The remainder of the sample was fitted with a stellar photosphere to derive the best-fitting luminosity and effective temperature. Distance and reddening were taken from the literature. The stars were plotted in a Hertzsprung-Russell diagram (HRD) and compared to evolutionary tracks for Cepheids and theoretical instability strips. For the large majority of stars, the position in the HRD is consistent with the instability strip for a CC or T2C. About 5% of the stars are outliers in the sense that they are much hotter or cooler than expected. A comparison to effective temperatures derived from spectroscopy suggests in some cases that the photometrically derived temperature is not correct and that this is likely linked to an incorrectly adopted reddening. Two three-dimensional reddening models have been used to derive alternative estimates of the reddening for the sample. There are significant systematic differences between the two estimates with a non-negligible scatter. In this work the presence of a small near-infrared (NIR) excess, as has been proposed in the literature for a few well-known Cepheids, is investigated. Firstly, this was done by using a sample of about a dozen stars for which a mid-infrared spectrum is available. This data is particularly constraining as the shape of the observed spectrum should match that of the photosphere and any dust spectrum, both dust continuum and any spectral features of, for example, silicates or aluminium oxide. This comparison provides constraints on the dust composition, in agreement with a previous work in the literature. Secondly, the SEDs of all stars were fitted with a dust model to see if a statistically significant better fit could be obtained. The results were compared to recent work. Eight new candidates for exhibiting a NIR excess are proposed, solely based on the photometric SEDs. Obtaining mid-infrared spectra would be needed to confirm this excess. Finally, period-bolometric luminosity and period-radius relations are presented for samples of over 370 fundamental-mode CCs.

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Gate tunable self-powered few-layer black phosphorus broadband photodetector

Physical Chemistry Chemical Physics ◽

10.1039/d0cp05292b ◽

2021 ◽

Vol 23 (1) ◽

pp. 399-404

Author(s):

Xiaofei Guo ◽

Liwen Zhang ◽

Jun Chen ◽

Xiaohong Zheng ◽

Lei Zhang

Keyword(s):

Stark Effect ◽

Far Infrared ◽

Black Phosphorus ◽

Infrared Range ◽

Mid Infrared ◽

Self Powered ◽

Photodetector Device

Due to the giant Stark effect in few-layer black phosphorus (BP), a self-powered and gate-controlled pure few-layer BP based photodetector device is proposed, which can cover the photodetection range from mid-infrared range (MIR) to far-infrared range (FIR).

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Properties of mid- to far-infrared dust emission in the nearby superwind galaxy M82

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312009076 ◽

2011 ◽

Vol 7 (S284) ◽

pp. 210-212

Author(s):

Ko Arimatsu ◽

Takashi Onaka ◽

Itsuki Sakon ◽

Fumi Egusa ◽

Hidehiro Kaneda

Keyword(s):

Aromatic Hydrocarbons ◽

Infrared Imaging ◽

Dust Emission ◽

Infrared Camera ◽

Far Infrared ◽

Emission Characteristics ◽

Imaging Data ◽

Mid Infrared ◽

Polycyclic Aromatic ◽

Intergalactic Space

AbstractUsing the reconstructed imaging data obtained with the Infrared Camera (IRC) on board AKARI, mid-infrared (MIR; 5-30 μm) emission characteristics of the superwind galaxy M82 are studied. The MIR images at four wavelengths (7, 11, 15, and 24 μm) show extended (out to distances of 4 kpc) emission mainly from polycyclic aromatic hydrocarbons (PAHs). The MIR SED of M82 halo is surprisingly constant. Using far-infrared imaging data obtained by Herschel/SPIRE, we reveal that the PAH abundance relative to the big (sub-micron sized) grains radially increases by about a factor of three. These results imply that PAHs may be formed in small and dense molecular clumps in the halo and efficiently supplied to the intergalactic space by the galactic superwind.

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