scholarly journals ALMA uncovers the [C ii] emission and warm dust continuum in a z = 8.31 Lyman break galaxy

2020 ◽  
Vol 493 (3) ◽  
pp. 4294-4307 ◽  
Author(s):  
Tom J L C Bakx ◽  
Yoichi Tamura ◽  
Takuya Hashimoto ◽  
Akio K Inoue ◽  
Minju M Lee ◽  
...  
Keyword(s):  
Confidence Limit ◽  
Rest Frame ◽  
Dust Emission ◽  
Continuum Emission ◽  
Dust Production ◽  
Radiation Fields ◽  
Dust Mass ◽  
Production Problem ◽  
Dust Component ◽  
Photodissociation Regions

ABSTRACT We report on the detection of the [C ii] 157.7 μm emission from the Lyman break galaxy (LBG) MACS0416_Y1 at z = 8.3113, by using the Atacama Large Millimeter/submillimeter Array (ALMA). The luminosity ratio of [O iii] 88 μm (from previous campaigns) to [C ii] is 9.3 ± 2.6, indicative of hard interstellar radiation fields and/or a low covering fraction of photodissociation regions. The emission of [C ii] is cospatial to the 850 μm dust emission (90 μm rest frame, from previous campaigns), however the peak [C ii] emission does not agree with the peak [O iii] emission, suggesting that the lines originate from different conditions in the interstellar medium. We fail to detect continuum emission at 1.5 mm (160 μm rest frame) down to 18 μJy (3σ). This non-detection places a strong limits on the dust spectrum, considering the 137 ± 26 μJy continuum emission at 850 μm. This suggests an unusually warm dust component (T > 80 K, 90 per cent confidence limit), and/or a steep dust-emissivity index (βdust > 2), compared to galaxy-wide dust emission found at lower redshifts (typically T ∼ 30–50 K, βdust ∼ 1–2). If such temperatures are common, this would reduce the required dust mass and relax the dust production problem at the highest redshifts. We therefore warn against the use of only single-wavelength information to derive physical properties, recommend a more thorough examination of dust temperatures in the early Universe, and stress the need for instrumentation that probes the peak of warm dust in the Epoch of Reionization.

scholarly journals A Gas and Dust Rich Giant Elliptical Galaxy

2005 ◽  
Vol 13 ◽  
pp. 872-874
Author(s):  
O. Krause ◽  
U. Lisenfeld ◽  
U. Klaas ◽  
D. Lemke ◽  
M. Haas ◽  
...  
Keyword(s):  
Elliptical Galaxy ◽  
Dust Emission ◽  
Optical Spectra ◽  
Radio Continuum ◽  
Continuum Emission ◽  
Bolometric Luminosity ◽  
Thermal Radio ◽  
Visual Extinction ◽  
Dust Mass ◽  
Ir Emission

AbstractThe bolometric luminosity of LFIR = 2×1012 L⊙ makes ISOSS J 15079+7247 one of the most luminous and unusual galaxies detected by the 170 μm ISOPHOT Serendipity Survey (ISOSS). The detection of CO (1-0) emission identifies a giant elliptical galaxy at redshift z = 0.2136 as the counterpart of the FIR source. The derived high gas mass of 3 × 1010 M⊙ favours the picture that the dust emission is associated with this elliptical galaxy. The ultraluminous IR emission can be explained by a hidden starburst in the center of the elliptical. This is supported by the strength of non-thermal radio continuum emission. The huge dust mass of 5×108 M⊙ corresponds to a visual extinction of AV ~ 1000 mag, being consistent with the non-detection of any signatures of a strong starburst in ISOSS J 15079+7247 in optical spectra.

Detections of far-infrared [OIII] and dust emission in a galaxy at z = 8.312: Early metal enrichment in the heart of the reionization era

2019 ◽  
Vol 15 (S341) ◽  
pp. 211-215
Author(s):  
Y. Tamura ◽  
K. Mawatari ◽  
T. Hashimoto ◽  
A. K. Inoue ◽  
E. Zackrissonm ◽  
...  
Keyword(s):  
Spectral Energy Distribution ◽  
Dust Emission ◽  
Far Infrared ◽  
Continuum Emission ◽  
Spectral Energy ◽  
Star Forming ◽  
Stellar Component ◽  
Dust Mass ◽  
Infrared Spectral ◽  
Emissivity Model

AbstractWe present ALMA detection of the [O iii] 88 μm line and 850 μm dust continuum emission in a Y-dropout Lyman break galaxy, MACS0416_Y1. The [O iii] detection confirms the object with a spectroscopic redshift to be z = 8.3118±0.0003. The 850 μm continuum intensity (0.14 mJy) implies a large dust mass on the order of 4×106M⊙. The ultraviolet-to-far infrared spectral energy distribution modeling, where the [O iii] emissivity model is incorporated, suggests the presence of a young (τage ≍ 4 Myr), star-forming (SFR ≍ 60M⊙yr−1), and moderately metal-polluted (Z ≍ 0.2Z⊙) stellar component with a stellar mass of 3 × 108M⊙. An analytic dust mass evolution model with a single episode of star formation does not reproduce the metallicity and dust mass in ≍ 4 Myr, suggesting an underlying evolved stellar component as the origin of the dust mass.

scholarly journals Microwave observations of spinning dust emission in NGC6946⋆

2010 ◽  
Vol 406 (1) ◽  
pp. L45-L49 ◽  
Author(s):  
Anna M. M. Scaife ◽  
Bojan Nikolic ◽  
David A. Green ◽  
Rainer Beck ◽  
Matthew L. Davies ◽  
...  
Keyword(s):  
Dust Emission ◽  
Continuum Emission ◽  
Published Data ◽  
Nearby Galaxy ◽  
Hii Region ◽  
Wave Measurements ◽  
Dust Component ◽  
Emission Models ◽  
Analysis Package ◽  
Ultracompact Hii

ABSTRACT We report new cm-wave measurements at five frequencies between 15 and 18GHz of the continuum emission from the reportedly anomalous ‘region 4’ of the nearby galaxy NGC6946. We find that the emission in this frequency range is significantly in excess of that measured at 8.5GHz, but has a spectrum from 15 to 18GHz consistent with optically thin free–free emission from an ultracompact Hii region. In combination with previously published data, we fit four emission models containing different continuum components using the Bayesian spectrum analysis package radiospec. These fits show that, in combination with data at other frequencies, a model with a spinning dust component is slightly preferred to those that possess better-established emission mechanisms.

scholarly journals Predictions for the spatial distribution of the dust continuum emission in $\boldsymbol {1\,\lt\, z\,\lt\, 5}$ star-forming galaxies

2019 ◽  
Vol 488 (2) ◽  
pp. 1779-1789 ◽  
Author(s):  
R K Cochrane ◽  
C C Hayward ◽  
D Anglés-Alcázar ◽  
J Lotz ◽  
T Parsotan ◽  
...  
Keyword(s):  
Star Formation ◽  
Formation Rate ◽  
Dust Emission ◽  
Far Infrared ◽  
Continuum Emission ◽  
Spectral Energy ◽  
Star Forming ◽  
Dust Mass ◽  
Far Ultraviolet ◽  
Stellar Masses

ABSTRACT We present the first detailed study of the spatially resolved dust continuum emission of simulated galaxies at 1 < z < 5. We run the radiative transfer code skirt on a sample of submillimetre-bright galaxies drawn from the Feedback In Realistic Environments (FIRE) project. These simulated galaxies reach Milky Way masses by z = 2. Our modelling provides predictions for the full rest-frame far-ultraviolet-to-far-infrared spectral energy distributions of these simulated galaxies, as well as 25-pc resolution maps of their emission across the wavelength spectrum. The derived morphologies are notably different in different wavebands, with the same galaxy often appearing clumpy and extended in the far-ultraviolet yet an ordered spiral at far-infrared wavelengths. The observed-frame 870-$\mu$m half-light radii of our FIRE-2 galaxies are ${\sim} 0.5\rm {-}4\, \rm {kpc}$, consistent with existing ALMA observations of galaxies with similarly high redshifts and stellar masses. In both simulated and observed galaxies, the dust continuum emission is generally more compact than the cold gas and the dust mass, but more extended than the stellar component. The most extreme cases of compact dust emission seem to be driven by particularly compact recent star formation, which generates steep dust temperature gradients. Our results confirm that the spatial extent of the dust continuum emission is sensitive to both the dust mass and star formation rate distributions.

scholarly journals Resolved spectral variations of the centimetre-wavelength continuum from the ρ Oph W photo-dissociation-region

2021 ◽  
Author(s):  
Simon Casassus ◽  
Matías Vidal ◽  
Carla Arce-Tord ◽  
Clive Dickinson ◽  
Glenn J White ◽  
...  
Keyword(s):  
Molecular Cloud ◽  
Dust Emission ◽  
Image Synthesis ◽  
Microwave Emission ◽  
Radio Continuum ◽  
Continuum Emission ◽  
Parametric Image ◽  
Physical Conditions ◽  
Morphological Differences ◽  
Dust Grain

Abstract Cm-wavelength radio continuum emission in excess of free-free, synchrotron and Rayleigh-Jeans dust emission (excess microwave emission, EME), and often called ‘anomalous microwave emission’, is bright in molecular cloud regions exposed to UV radiation, i.e. in photo-dissociation regions (PDRs). The EME correlates with IR dust emission on degree angular scales. Resolved observations of well-studied PDRs are needed to compare the spectral variations of the cm-continuum with tracers of physical conditions and of the dust grain population. The EME is particularly bright in the regions of the ρ Ophiuchi molecular cloud (ρ Oph) that surround the earliest type star in the complex, HD 147889, where the peak signal stems from the filament known as the ρ Oph-W PDR. Here we report on ATCA observations of ρ Oph-W that resolve the width of the filament. We recover extended emission using a variant of non-parametric image synthesis performed in the sky plane. The multi-frequency 17 GHz to 39 GHz mosaics reveal spectral variations in the cm-wavelength continuum. At ∼30 arcsec resolutions, the 17-20 GHz intensities follow tightly the mid-IR, Icm∝I(8 μm), despite the breakdown of this correlation on larger scales. However, while the 33-39 GHz filament is parallel to IRAC 8 μm, it is offset by 15–20 arcsec towards the UV source. Such morphological differences in frequency reflect spectral variations, which we quantify spectroscopically as a sharp and steepening high-frequency cutoff, interpreted in terms of the spinning dust emission mechanism as a minimum grain size acutoff ∼ 6 ± 1 Å that increases deeper into the PDR.

scholarly journals Analysis of the Interstellar Medium Properties of the Herschel Reference Survey Galaxies

2012 ◽  
Vol 8 (S292) ◽  
pp. 284-284
Author(s):  
Laure Ciesla ◽  
Keyword(s):  
Interstellar Medium ◽  
Physical Properties ◽  
Radiation Field ◽  
Statistical Study ◽  
Dust Mass ◽  
Multi Wavelength ◽  
Nearby Galaxies ◽  
Photodissociation Regions ◽  
K Band

AbstractThe Herschel Reference Survey is a guaranteed time key project aimed at studying the physical properties of the interstellar medium (ISM) of 323 nearby galaxies, covered by multi-wavelength data. This volume limited, K-band selected sample is composed of galaxies spanning the whole range of morphological types and environments. We conduct a statistical study on the ISM properties of nearby galaxies based on the analysis of their SED. To achieve this goal, we fit the data with the models of Draine & Li (2007) to obtain the intensity of interstellar radiation field, the PAH abundance, the contribution of photodissociation regions, and the dust mass.

scholarly journals Dust properties and star formation of approximately a thousand local galaxies

2019 ◽  
Vol 631 ◽  
pp. A38 ◽  
Author(s):  
S. Lianou ◽  
P. Barmby ◽  
A. A. Mosenkov ◽  
M. Lehnert ◽  
O. Karczewski
Keyword(s):  
Star Formation ◽  
Spectral Energy Distribution ◽  
Dust Emission ◽  
Distribution Functions ◽  
Spectral Energy ◽  
Emission Properties ◽  
Galaxy Type ◽  
Dust Mass ◽  
The Galaxy ◽  
Stellar Masses

Aims. We derived the dust properties for 753 local galaxies and examine how these relate to some of their physical properties. We present the derived dust emission properties, including model spectral energy distribution (SEDs), star formation rates (SFRs) and stellar masses, as well as their relations. Methods. We modelled the global dust-SEDs for 753 galaxies, treated statistically as an ensemble within a hierarchical Bayesian dust-SED modelling approach, so as to derive their infrared (IR) emission properties. To create the observed dust-SEDs, we used a multi-wavelength set of observations, ranging from near-IR to far-IR-to-submillimeter wavelengths. The model-derived properties are the dust masses (Mdust), the average interstellar radiation field intensities (Uav), the mass fraction of very small dust grains (“QPAH” fraction), as well as their standard deviations. In addition, we used mid-IR observations to derive SFR and stellar masses, quantities independent of the dust-SED modelling. Results. We derive distribution functions of the properties for the galaxy ensemble and as a function of galaxy type. The mean value of Mdust for the early-type galaxies (ETGs) is lower than that for the late-type and irregular galaxies (LTGs and Irs, respectively), despite ETGs and LTGs having stellar masses spanning across the whole range observed. The Uav and “QPAH” fraction show no difference among different galaxy types. When fixing Uav to the Galactic value, the derived “QPAH” fraction varies across the Galactic value (0.071). The specific SFR increases with galaxy type, while this is not the case for the dust-specific SFR (SFR/Mdust), showing an almost constant star formation efficiency per galaxy type. The galaxy sample is characterised by a tight relationship between the dust mass and the stellar mass for the LTGs and Irs, while ETGs scatter around this relation and tend towards smaller dust masses. While the relation indicates that Mdust may fundamentally be linked to M⋆, metallicity and Uav are the second parameter driving the scatter, which we investigate in a forthcoming work. We used the extended Kennicutt–Schmidt (KS) law to estimate the gas mass and the gas-to-dust mass ratio (GDR). The gas mass derived from the extended KS law is on average ∼20% higher than that derived from the KS law, and a large standard deviation indicates the importance of the average star formation present to regulate star formation and gas supply. The average GDR for the LTGs and Irs is 370, and including the ETGs gives an average of 550.

scholarly journals The infrared view of dust and molecules around V4334 Sgr (Sakurai’s object): a 20-yr retrospective

2020 ◽  
Vol 493 (1) ◽  
pp. 1277-1291 ◽  
Author(s):  
A Evans ◽  
R D Gehrz ◽  
C E Woodward ◽  
D P K Banerjee ◽  
T R Geballe ◽  
...  
Keyword(s):  
Amorphous Carbon ◽  
Near Infrared ◽  
Dust Emission ◽  
Infrared Excess ◽  
Object A ◽  
Bolometric Luminosity ◽  
Dust Mass ◽  
Mass Ejection ◽  
Lower Limits ◽  
Hydrogenated Amorphous

ABSTRACT We present an analysis of the evolution of circumstellar dust and molecules in the environment of the very late thermal pulse object V4334 Sgr (Sakurai’s object) over an ∼20-yr period, drawing on ground-, airborne-, and space-based infrared photometry and spectroscopy. The dust emission, which started in 1997, resembles a blackbody that cooled from ∼1200 K in 1998 August to ∼180 K in 2016 July. The dust mass, assuming amorphous carbon, was ∼5 × 10−10 M⊙ in 1998 August, and we estimate that the total dust mass was ∼2 × 10−5 M⊙ by ∼2016. The appearance of a near-infrared excess in 2008 suggests that a new episode of (or renewed) mass-loss began then. We infer lower limits on the bolometric luminosity of the embedded star from that of the dust shell, which rose to ∼16 000 L⊙ before declining to ∼3000 L⊙. There is evidence for weak 6–7 μm absorption, which we attribute to hydrogenated amorphous carbon formed in material ejected by Sakurai’s object during a mass ejection phase that preceded the 1997 event. We detect small hydrocarbon and other molecules in the spectra, and trace the column densities in hydrogen cyanide (HCN) and acetylene (C2H2). We use the former to determine the 12C/13C ratio to be 6.4 ± 0.7, 14 times smaller than the Solar system value.

scholarly journals The dust mass function from z ∼0 to z ∼2.5

2019 ◽  
Vol 491 (4) ◽  
pp. 5073-5082 ◽  
Author(s):  
F Pozzi ◽  
F Calura ◽  
G Zamorani ◽  
I Delvecchio ◽  
C Gruppioni ◽  
...  
Keyword(s):  
Mass Density ◽  
Dust Emission ◽  
Black Body ◽  
Mass Function ◽  
Steep Slope ◽  
Number Density ◽  
Local Universe ◽  
Redshift Range ◽  
Dust Mass ◽  
First Time

ABSTRACT We derive for the first time the dust mass function (DMF) in a wide redshift range, from z ∼ 0.2 up to z ∼ 2.5. In order to trace the dust emission, we start from a far-IR (160-μm) Herschel selected catalogue in the COSMOS field. We estimate the dust masses by fitting the far-IR data (λrest$\,\, \buildrel\gt \over \sim \,\,$50 μm) with a modified black body function and we present a detailed analysis to take into account the incompleteness in dust masses from a far-IR perspective. By parametrizing the observed DMF with a Schechter function in the redshift range 0.1 < z ≤ 0.25, where we are able to sample faint dust masses, we measure a steep slope (α ∼1.48), as found by the majority of works in the Local Universe. We detect a strong dust mass evolution, with $M_{\rm d}^{\star }$ at z ∼ 2.5 almost 1 dex larger than in the local Universe, combined with a decrease in their number density. Integrating our DMFs, we estimate the dust mass density (DMD), finding a broad peak at z ∼ 1, with a decrease by a factor of ∼ 3 towards z ∼ 0 and z ∼ 2.5. In general, the trend found for the DMD mostly agrees with the derivation of Driver et al., another DMD determination based also on far-IR detections, and with other measures based on indirect tracers.

scholarly journals The dust never settles: collisional production of gas and dust in evolved planetary systems

2020 ◽  
Vol 496 (4) ◽  
pp. 5233-5242 ◽  
Author(s):  
Andrew Swan ◽  
Jay Farihi ◽  
Thomas G Wilson ◽  
Steven G Parsons
Keyword(s):  
Time Scales ◽  
White Dwarf ◽  
Dust Emission ◽  
Canonical Model ◽  
Minor Planets ◽  
Infrared Photometry ◽  
Dust Production ◽  
Thick Disc ◽  
Observed Behaviour ◽  
Host Stars

ABSTRACT Multi-epoch infrared photometry from Spitzer is used to monitor circumstellar discs at white dwarfs, which are consistent with disrupted minor planets whose debris is accreted and chemically reflected by their host stars. Widespread infrared variability is found across the population of 37 stars with two or more epochs. Larger flux changes occur on longer time-scales, reaching several tens of per cent over baselines of a few years. The canonical model of a geometrically thin, optically thick disc is thus insufficient, as it cannot give rise to the observed behaviour. Optically thin dust best accounts for the variability, where collisions drive dust production and destruction. Notably, the highest infrared variations are seen in systems that show Ca ii emission, supporting planetesimal collisions for all known debris discs, with the most energetic occurring in those with detected gaseous debris. The sample includes the only polluted white dwarf with a circumbinary disc, where the signal of the day–night cycle of its irradiated substellar companion appears diluted by dust emission.

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