scholarly journals A dense, solar metallicity ISM in the z = 4.2 dusty star-forming galaxy SPT 0418−47

2019 ◽  
Vol 631 ◽  
pp. A167 ◽  
Author(s):  
Carlos De Breuck ◽  
Axel Weiß ◽  
Matthieu Béthermin ◽  
Daniel Cunningham ◽  
Yordanka Apostolovski ◽  
...  
Keyword(s):  
Fine Structure ◽  
Interstellar Medium ◽  
Far Infrared ◽  
Line Ratio ◽  
Star Forming ◽  
Physical Conditions ◽  
Solar Metallicity ◽  
Fine Structure Lines ◽  
Compact Array

We present a study of six far-infrared fine structure lines in the z = 4.225 lensed dusty star-forming galaxy SPT 0418−47 to probe the physical conditions of its interstellar medium (ISM). In particular, we report Atacama Pathfinder EXperiment (APEX) detections of the [OI] 145 μm and [OIII] 88 μm lines and Atacama Compact Array (ACA) detections of the [NII] 122 and 205 μm lines. The [OI] 145 μm/[CII] 158 μm line ratio is ∼5× higher compared to the average of local galaxies. We interpret this as evidence that the ISM is dominated by photo-dissociation regions with high gas densities. The line ratios, and in particular those of [OIII] 88 μm and [NII] 122 μm imply that the ISM in SPT 0418−47 is already chemically enriched to nearly solar metallicity. While the strong gravitational amplification was required to detect these lines with APEX, larger samples can be observed with the Atacama Large Millimeter/submillimeter Array (ALMA), and should allow observers to determine if the dense, solar metallicity ISM is common among these highly star-forming galaxies.

scholarly journals The Orion Nebula in the Far-Infrared: High-J CO and fine-structure lines mapped by FIFI-LS/SOFIA

2015 ◽  
Vol 12 (S316) ◽  
pp. 153-154
Author(s):  
Randolf Klein ◽  
Leslie W. Looney ◽  
Erin Cox ◽  
Christian Fischer ◽  
Christof Iserlohe ◽  
...  
Keyword(s):  
Fine Structure ◽  
Far Infrared ◽  
Molecular Gas ◽  
Orion Nebula ◽  
Star Forming ◽  
Physical Conditions ◽  
Molecular Outflow ◽  
Integral Field ◽  
Fine Structure Lines ◽  
Co Observations

AbstractThe Orion Nebula is the closest massive star forming region allowing us to study the physical conditions in such a region with high spatial resolution. We used the far infrared integral-field spectrometer, FIFI-LS, on-board the airborne observatory SOFIA to study the atomic and molecular gas in the Orion Nebula at medium spectral resolution.The large maps obtained with FIFI-LS cover the nebula from the BN/KL-object to the bar in several fine structure lines. They allow us to study the conditions of the photon-dominated region and the interface to the molecular cloud with unprecedented detail.Another investigation targeted the molecular gas in the BN/KL region of the Orion Nebula, which is stirred up by a violent explosion about 500 years ago. The explosion drives a wide angled molecular outflow. We present maps of several high-J CO observations, allowing us to analyze the heated molecular gas.

scholarly journals Probing the Baryon Cycle of Galaxies with SPICA Mid- and Far-Infrared Observations

2018 ◽  
Vol 35 ◽  
Author(s):  
F. F. S. van der Tak ◽  
S. C. Madden ◽  
P. Roelfsema ◽  
L. Armus ◽  
M. Baes ◽  
...  
Keyword(s):  
Fine Structure ◽  
Star Formation ◽  
Supernova Remnants ◽  
Interstellar Dust ◽  
Far Infrared ◽  
Turbulent Energy ◽  
Star Forming ◽  
Infrared Telescope ◽  
Nearby Galaxies ◽  
Fine Structure Lines

AbstractThe SPICA mid- and far-infrared telescope will address fundamental issues in our understanding of star formation and ISM physics in galaxies. A particular hallmark of SPICA is the outstanding sensitivity enabled by the cold telescope, optimised detectors, and wide instantaneous bandwidth throughout the mid- and far-infrared. The spectroscopic, imaging, and polarimetric observations that SPICA will be able to collect will help in clarifying the complex physical mechanisms which underlie the baryon cycle of galaxies. In particular, (i) the access to a large suite of atomic and ionic fine-structure lines for large samples of galaxies will shed light on the origin of the observed spread in star-formation rates within and between galaxies, (ii) observations of HD rotational lines (out to ~10 Mpc) and fine structure lines such as [C ii] 158 μm (out to ~100 Mpc) will clarify the main reservoirs of interstellar matter in galaxies, including phases where CO does not emit, (iii) far-infrared spectroscopy of dust and ice features will address uncertainties in the mass and composition of dust in galaxies, and the contributions of supernovae to the interstellar dust budget will be quantified by photometry and monitoring of supernova remnants in nearby galaxies, (iv) observations of far-infrared cooling lines such as [O i] 63 μm from star-forming molecular clouds in our Galaxy will evaluate the importance of shocks to dissipate turbulent energy. The paper concludes with requirements for the telescope and instruments, and recommendations for the observing strategy.

scholarly journals Far-Infrared [C II] Properties of Low-Metallicity Galaxies

1998 ◽  
Vol 11 (1) ◽  
pp. 123-124
Author(s):  
K. Mochizuki ◽  
T. Onaka ◽  
T. Nakagawa
Keyword(s):  
Fine Structure ◽  
Interstellar Medium ◽  
Dwarf Galaxies ◽  
Flux Ratio ◽  
Far Infrared ◽  
Line Flux ◽  
Massive Galaxies ◽  
Physical Conditions ◽  
Different Types ◽  
Low Metallicity

The line flux ratio of the [C II] 158 μm fine-structure (2P3/2 → 2P3/2) emission to CO rotational emission is a probe of the intensity of the interstellar UV radiation in galaxies. The largest values for the [C II]/CO (J = 1-0) line ratios are found in starburst galaxies, none of which, however, show values larger than 6 ×103 (Stacey et al. 1991). The exception ([CII]/CO ≃ 2 × 104) are galaxies of Magellanic type which have low metallicity, an intense interstellar UV field, and irregular morphology (Table 1). Mochizuki et al. (1994) showed that the two conditions, a low metallicity and an intense UV field are expected to result in the large [C II]/CO ratios in the Magellanic types. These conditions are likely to be common in more massive galaxies as well, but at an early epoch in their evolution. This suggests that bright [C II] emission can be a good indicator of young galaxies. However, the metal-poor galaxies previously observed in the [C II] line were exclusively Magellanic types. Observations of different types of dwarf galaxies are necessary to help us understand the physical conditions in the interstellar medium of low-metallicity systems.

scholarly journals Full of Orions: a 200-pc mapping of the interstellar medium in the redshift-3 lensed dusty star-forming galaxy SDP.81

2020 ◽  
Vol 494 (4) ◽  
pp. 5542-5567 ◽  
Author(s):  
Matus Rybak ◽  
J A Hodge ◽  
S Vegetti ◽  
P van der Werf ◽  
P Andreani ◽  
...  
Keyword(s):  
Field Strength ◽  
Interstellar Medium ◽  
Far Infrared ◽  
Source Plane ◽  
Star Forming ◽  
Physical Conditions ◽  
Orion Trapezium ◽  
Thermal Saturation ◽  
Continuum Data ◽  
Far Ultraviolet

ABSTRACT We present a sub-kpc resolved study of the interstellar medium properties in SDP.81, a $z$ = 3.042 strongly gravitationally lensed, dusty star-forming galaxy, based on high-resolution, multiband ALMA observations of the far-infrared (FIR) continuum, CO ladder, and the [C ii] line. Using a visibility-plane lens modelling code, we achieve a median source-plane resolution of ∼200 pc. We use photon-dominated region (PDR) models to infer the physical conditions – far-ultraviolet (FUV) field strength, density, and PDR surface temperature – of the star-forming gas on 200-pc scales, finding a FUV field strength of ∼103−104G0, gas density of ∼105 cm−3, and cloud surface temperatures up to 1500 K, similar to those in the Orion Trapezium region. The [C ii] emission is significantly more extended than that FIR continuum: ∼50 per cent of [C ii] emission arises outside the FIR-bright region. The resolved [C ii]/FIR ratio varies by almost 2 dex across the source, down to ∼2 × 10−4 in the star-forming clumps. The observed [C ii]/FIR deficit trend is consistent with thermal saturation of the C+ fine-structure-level occupancy at high gas temperatures. We make the source-plane reconstructions of all emission lines and continuum data publicly available.

scholarly journals Properties of galaxies at z ≈ 7 – 9 revealed by ALMA

2019 ◽  
Vol 15 (S352) ◽  
pp. 13-18
Author(s):  
Takuya Hashimoto
Keyword(s):  
Fine Structure ◽  
Gas Phase ◽  
Far Infrared ◽  
Continuum Emission ◽  
High Luminosity ◽  
Star Forming ◽  
High Ionization ◽  
Very High ◽  
Modern Astronomy ◽  
Fine Structure Lines

AbstractUnderstanding properties of galaxies in the epoch of reionization (EoR) is a frontier in the modern astronomy. With the advent of ALMA, it has become possible to detect far-infrared fine structure lines (e.g. [CII] 158 μm and [OIII] 88 μm) and dust continuum emission in star-forming galaxies in the EoR. Among these lines, our team is focusing on [OIII] 88 μm observations in high-z galaxies. After the first detection of [OIII] in the epoch of reionization (EoR) in 2016 from our team at z = 7.21, there are now more than ten [OIII] detections at z > 6 up to z = 9.11. Interestingly, high-z galaxies typically have very high [OIII]-to-[CII] luminosity ratio ranging from 3 to 12 or higher, demonstrating [OIII] is a powerful tracer at high-z. The high luminosity ratios may imply that high-z galaxies have low gas-phase metallicity and/or high ionization states.

scholarly journals The prospects for observing [O iii] 52 micron emission from galaxies during the Epoch of Reionization

2021 ◽  
Vol 504 (1) ◽  
pp. 723-730
Author(s):  
Shengqi Yang ◽  
Adam Lidz ◽  
Gergö Popping
Keyword(s):  
Fine Structure ◽  
Interstellar Medium ◽  
Emission Line ◽  
Parameter Space ◽  
Gas Density ◽  
Star Forming ◽  
Upper Limits ◽  
Redshift Galaxies

ABSTRACT The [O iii] 88 $\mu$m fine-structure emission line has been detected into the Epoch of Reionization (EoR) from star-forming galaxies at redshifts 6 < z ≲ 9 with ALMA. These measurements provide valuable information regarding the properties of the interstellar medium (ISM) in the highest redshift galaxies discovered thus far. The [O iii] 88 $\mu$m line observations leave, however, a degeneracy between the gas density and metallicity in these systems. Here, we quantify the prospects for breaking this degeneracy using future ALMA observations of the [O iii] 52 $\mu$m line. Among the current set of 10 [O iii] 88 $\mu$m emitters at 6 < z ≲ 9, we forecast 52 $\mu$m detections (at 6σ) in SXDF-NB1006-2, B14-6566, J0217-0208, and J1211-0118 within on-source observing times of 2–10 h, provided their gas densities are larger than about nH ≳ 102–103 cm−3. Other targets generally require much longer integration times for a 6σ detection. Either successful detections of the 52 $\mu$m line or reliable upper limits will lead to significantly tighter constraints on ISM parameters. The forecasted improvements are as large as ∼3 dex in gas density and ∼1 dex in metallicity for some regions of parameter space. We suggest SXDF-NB1006-2 as a promising first target for 52 $\mu$m line measurements. We discuss how such measurements will help in understanding the mass–metallicity relationship during the EoR.

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