scholarly journals Origins Space Telescope: Predictions for far-IR spectroscopic surveys

2019 ◽  
Vol 36 ◽  
Author(s):  
Matteo Bonato ◽  
Gianfranco De Zotti ◽  
David Leisawitz ◽  
Mattia Negrello ◽  
Marcella Massardi ◽  
...  
Keyword(s):  
Aromatic Hydrocarbons ◽  
Time Line ◽  
Space Telescope ◽  
Star Forming ◽  
The Galaxy ◽  
Deep Survey ◽  
Polycyclic Aromatic ◽  
Order Of Magnitude ◽  
Ir Spectroscopic ◽  
Open Issues

AbstractWe illustrate the extraordinary potential of the (far-IR) Origins Survey Spectrometer (OSS) on board the Origins Space Telescope (OST) to address a variety of open issues on the co-evolution of galaxies and AGNs. We present predictions for blind surveys, each of 1000 h, with different mapped areas (a shallow survey covering an area of 10 deg2 and a deep survey of 1 deg2) and two different concepts of the OST/OSS: with a 5.9 m telescope (Concept 2, our reference configuration) and with a 9.1 m telescope (Concept 1, previous configuration). In 1 000 h, surveys with the reference concept will detect from ∼1.9×106 to ∼8.7×106 lines from ∼4.8×105 to 2.7×106 star-forming galaxies and from ∼1.4×104 to ∼3.8×104 lines from ∼1.3×104 to 3.5×104 AGNs. The shallow survey will detect substantially more sources than the deep one; the advantage of the latter in pushing detections to lower luminosities/higher redshifts turns out to be quite limited. The OST/OSS will reach, in the same observing time, line fluxes more than one order of magnitude fainter than the SPICA/SMI and will cover a much broader redshift range. In particular it will detect tens of thousands of galaxies at z ≥ 5, beyond the reach of that instrument. The polycyclic aromatic hydrocarbons lines are potentially bright enough to allow the detection of hundreds of thousands of star-forming galaxies up to z ∼ 8.5, i.e. all the way through the reionisation epoch. The proposed surveys will allow us to explore the galaxy–AGN co-evolution up to z ∼ 5.5−6 with very good statistics. OST Concept 1 does not offer significant advantages for the scientific goals presented here.

scholarly journals IR ring nebulae in the Milky Way and M33 galaxies

2021 ◽  
Author(s):  
A. P. Topchieva ◽  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Star Formation ◽  
Aromatic Hydrocarbons ◽  
Milky Way ◽  
Massive Stars ◽  
Theoretical Data ◽  
Star Forming ◽  
The Galaxy ◽  
Polycyclic Aromatic ◽  
Ring Nebulae

Studying the formation of massive stars in our Galaxy and in other galaxies is one of the possibilities to connect the information obtained for the regions of star formation in general. This study presents statistical and theoretical data on infrared ring nebulae (IRRN) in our Galaxy and the galaxy M33, which is located not far from us and in the plane of sky, which is convenient for selecting individual objects. In this paper, comparisons of fluxes for 258 star-forming complexes in M33, extragalactic of star formation complexes, and for IRRN in our Galaxy are shown. A theoretical calculation of the distribution of polycyclic aromatic hydrocarbons using DustEM has been carried out.

scholarly journals The strange case of the peculiar spiral galaxy NGC 5474

2020 ◽  
Vol 634 ◽  
pp. A124 ◽  
Author(s):  
M. Bellazzini ◽  
F. Annibali ◽  
M. Tosi ◽  
A. Mucciarelli ◽  
M. Cignoni ◽  
...  
Keyword(s):  
Old Age ◽  
Spiral Galaxy ◽  
The Other ◽  
Spiral Pattern ◽  
Stellar Content ◽  
Peculiar Star ◽  
Space Telescope ◽  
Stellar Disc ◽  
Star Forming ◽  
The Galaxy

We present the first analysis of the stellar content of the structures and substructures identified in the peculiar star-forming galaxy NGC 5474, based on Hubble Space Telescope resolved photometry from the LEGUS survey. NGC 5474 is a satellite of the giant spiral M 101, and it is known to have a prominent bulge that is significantly off-set from the kinematic centre of the underlying H I and stellar disc. The youngest stars (age ≲ 100 Myr) trace a flocculent spiral pattern extending out to ≳8 kpc from the centre of the galaxy. On the other hand, intermediate-age (age ≳ 500 Myr) and old (age ≳ 2 Gyr) stars dominate the off-centred bulge and a large substructure residing in the south-western part of the disc (SW over-density) and they are not correlated with the spiral arms. The old age of the stars in the SW over-density suggests that this may be another signature of any dynamical interactions that have shaped this anomalous galaxy. We suggest that a fly by with M 101, generally invoked as the origin of the anomalies, may not be sufficient to explain all the observations. A more local and more recent interaction may help to put all the pieces of this galactic puzzle together.

scholarly journals Subaru High-z Exploration of Low-Luminosity Quasars (SHELLQs). VIII. A less biased view of the early co-evolution of black holes and host galaxies

2019 ◽  
Vol 71 (6) ◽  
Author(s):  
Takuma Izumi ◽  
Masafusa Onoue ◽  
Yoshiki Matsuoka ◽  
Tohru Nagao ◽  
Michael A Strauss ◽  
...  
Keyword(s):  
Black Holes ◽  
Far Infrared ◽  
Supermassive Black Holes ◽  
Host Galaxies ◽  
Star Forming ◽  
Wide Range ◽  
The Galaxy ◽  
Order Of Magnitude ◽  
Local Relation ◽  
Almost All

Abstract We present ALMA [C ii] line and far-infrared (FIR) continuum observations of three $z \gt 6$ low-luminosity quasars ($M_{\rm 1450} \gt -25$ mag) discovered by our Subaru Hyper Suprime-Cam (HSC) survey. The [C ii] line was detected in all three targets with luminosities of $(2.4\mbox{--}9.5) \times 10^8\, L_{\odot }$, about one order of magnitude smaller than optically luminous ($M_{\rm 1450} \lesssim -25$ mag) quasars. The FIR continuum luminosities range from $\lt 9 \times 10^{10}\, L_{\odot }$ (3 $\sigma$ limit) to ${\sim } 2 \times 10^{12}\, L_{\odot }$, indicating a wide range in star formation rates in these galaxies. Most of the HSC quasars studied thus far show [C ii]/ FIR luminosity ratios similar to local star-forming galaxies. Using the [C ii]-based dynamical mass ($M_{\rm dyn}$) as a surrogate for bulge stellar mass ($M_{\rm\, bulge}$), we find that a significant fraction of low-luminosity quasars are located on or even below the local $M_{\rm\, BH}$–$M_{\rm\, bulge}$ relation, particularly at the massive end of the galaxy mass distribution. In contrast, previous studies of optically luminous quasars have found that black holes are overmassive relative to the local relation. Given the low luminosities of our targets, we are exploring the nature of the early co-evolution of supermassive black holes and their hosts in a less biased way. Almost all of the quasars presented in this work are growing their black hole mass at a much higher pace at $z \sim 6$ than the parallel growth model, in which supermassive black holes and their hosts grow simultaneously to match the local $M_{\rm\, BH}$–$M_{\rm\, bulge}$ relation at all redshifts. As the low-luminosity quasars appear to realize the local co-evolutionary relation even at $z \sim 6$, they should have experienced vigorous starbursts prior to the currently observed quasar phase to catch up with the relation.

scholarly journals ALMA Deep Field in SSA22

2020 ◽  
Vol 640 ◽  
pp. L8 ◽  
Author(s):  
Hideki Umehata ◽  
Ian Smail ◽  
A. M. Swinbank ◽  
Kotaro Kohno ◽  
Yoichi Tamura ◽  
...  
Keyword(s):  
Galaxy Formation ◽  
Near Infrared ◽  
Formation Rate ◽  
Stellar Mass ◽  
Star Forming ◽  
Submillimeter Galaxies ◽  
The Galaxy ◽  
Deep Survey ◽  
Multi Wavelength

Deep surveys with the Atacama Large Millimeter Array (ALMA) have uncovered a population of dusty star-forming galaxies which are faint or even undetected at optical to near-infrared wavelengths. Their faintness at short wavelengths makes the detailed characterization of the population challenging. Here we present a spectroscopic redshift identification and a characterization of one of these near-infrared-dark galaxies discovered by an ALMA deep survey. The detection of [C I](1–0) and CO(4–3) emission lines determines the precise redshift of the galaxy, ADF22.A2, to be z = 3.9913 ± 0.0008. On the basis of a multi-wavelength analysis, ADF22.A2 is found to be a massive, star-forming galaxy with a stellar mass of M∗ = 1.1−0.6+1.3 × 1011 M⊙ and SFR = 430−150+230 M⊙ yr−1. The molecular gas mass was derived to be M(H2)[CI] = (5.9 ± 1.5)×1010 M⊙, indicating a gas fraction of ≈35%, and the ratios of L[CI](1−0)/LIR and L[CI](1−0)/LCO(4−3) suggest that the nature of the interstellar medium in ADF22.A2 is in accordance with those of other bright submillimeter galaxies. The properties of ADF22.A2, including the redshift, star-formation rate, stellar mass, and depletion time scale (τdep ≈ 0.1−0.2 Gyr), also suggest that ADF22.A2 has the characteristics expected for the progenitors of quiescent galaxies at z ≳ 3. Our results demonstrate the power of ALMA contiguous mapping and line scan, which help us to obtain an unbiased view of galaxy formation in the early Universe.

scholarly journals Gas-phase infrared spectroscopy of the rubicene cation (C26H14•+)

2020 ◽  
Vol 636 ◽  
pp. A57 ◽  
Author(s):  
J. Bouwman ◽  
C. Boersma ◽  
M. Bulak ◽  
J. Kamer ◽  
P. Castellanos ◽  
...  
Keyword(s):  
Gas Phase ◽  
Aromatic Hydrocarbons ◽  
Emission Spectra ◽  
Ir Absorption ◽  
Vibrational Motion ◽  
Carbon Structure ◽  
Upper Limits ◽  
Polycyclic Aromatic ◽  
Spectroscopic Database ◽  
Ir Spectroscopic

Infrared bands at 3.3, 6.2, 7.6, 7.8, 8.6, and 11.2 μm have been attributed to polycyclic aromatic hydrocarbons (PAHs) and are observed toward a large number of galactic and extragalactic sources. Some interstellar PAHs possibly contain five-membered rings in their honeycomb carbon structure. The inclusion of such pentagon defects can occur during PAH formation, or as large PAHs are eroded by photo-dissociation to ultimately yield fullerenes. Pentagon formation is a process that is associated with the bowling of the PAH plane, that is, the ability to identify PAH pentagons in space holds the potential to directly link PAHs to cage and fullerene structures. It has been hypothesized that infrared (IR) activity around 1100 cm−1 may be a spectral marker for interstellar pentagons. We present an experimentally measured gas-phase IR absorption spectrum of the pentagon-containing rubicene cation (C26H14•+) to investigate if this band is present. The NASA Ames PAH IR Spectroscopic Database is scrutinized to see whether other rubicene-like species show IR activity in this wavelength range. We find that a specific molecular characteristic is responsible for this IR band. Namely, the vibrational motion attributed to this IR activity involves pentagon-containing harbors. An attempt to find this specific mode in Spitzer observations is undertaken and tentative detections around 9.3 μm are made toward the reflection nebula NGC 7023 and the H II-region IRAS 12063-6259. Simulated emission spectra are used to derive upper limits for the contributions of rubicene-like pentagonal PAH species to the IR band at 6.2 μm toward these sources.

scholarly journals Observational constraints on the likelihood of 26Al in planet-forming environments

2020 ◽  
Vol 644 ◽  
pp. L1
Author(s):  
Megan Reiter
Keyword(s):  
Solar System ◽  
Planet Formation ◽  
Radioactive Decay ◽  
High Mass ◽  
Mass Star ◽  
Early Solar System ◽  
Star Forming ◽  
Star Forming Regions ◽  
The Galaxy ◽  
Order Of Magnitude

Recent work suggests that 26Al may determine the water budget in terrestrial exoplanets as its radioactive decay dehydrates planetesimals leading to rockier compositions. Here I consider the observed distribution of 26Al in the Galaxy and typical star-forming environments to estimate the likelihood of 26Al enrichment during planet formation. I do not assume Solar-System-specific constraints as I am interested in enrichment for exoplanets generally. Observations indicate that high-mass stars dominate the production of 26Al with nearly equal contributions from their winds and supernovae. Observed 26Al abundances are comparable to those in the early Solar System in the high-mass star-forming regions where most stars (and thereby most planets) form. These high abundances appear to be maintained for a few million years, which is much longer than the 0.7 Myr half-life. Observed bulk 26Al velocities are an order of magnitude slower than expected from winds and supernovae. These observations are at odds with typical model assumptions that 26Al is provided instantaneously by high velocity mass loss from supernovae and winds. The regular replenishment of 26Al, especially when coupled with the small age differences that are common in high-mass star-forming complexes, may significantly increase the number of star- and planet-forming systems exposed to 26Al. Exposure does not imply enrichment, but the order of magnitude slower velocity of 26Al may alter the fraction that is incorporated into planet-forming material. Together, this suggests that the conditions for rocky planet formation are not rare, nor are they ubiquitous, as small regions such as Taurus, that lack high-mass stars to produce 26Al may be less likely to form rocky planets. I conclude with suggested directions for future studies.

scholarly journals Nitro-polycyclic aromatic hydrocarbons – gas–particle partitioning, mass size distribution, and formation along transport in marine and continental background air

2017 ◽  
Vol 17 (10) ◽  
pp. 6257-6270 ◽  
Author(s):  
Gerhard Lammel ◽  
Marie D. Mulder ◽  
Pourya Shahpoury ◽  
Petr Kukučka ◽  
Hana Lišková ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Dispersion Model ◽  
Aegean Sea ◽  
Particle Dispersion ◽  
Linear Free Energy Relationship ◽  
Lagrangian Particle ◽  
Polycyclic Aromatic ◽  
Order Of Magnitude ◽  
Background Air

Abstract. Nitro-polycyclic aromatic hydrocarbons (NPAH) are ubiquitous in polluted air but little is known about their abundance in background air. NPAHs were studied at one marine and one continental background site, i.e. a coastal site in the southern Aegean Sea (summer 2012) and a site in the central Great Hungarian Plain (summer 2013), together with the parent compounds, PAHs. A Lagrangian particle dispersion model was used to track air mass history. Based on Lagrangian particle statistics, the urban influence on samples was quantified for the first time as a fractional dose to which the collected volume of air had been exposed. At the remote marine site, the 3–4-ring NPAH (sum of 11 targeted species) concentration was 23.7 pg m−3 while the concentration of 4-ring PAHs (6 species) was 426 pg m−3. The most abundant NPAHs were 2-nitrofluoranthene (2NFLT) and 3-nitrophenanthrene. Urban fractional doses in the range of < 0.002–5.4 % were calculated. At the continental site, the Σ11 3–4-ring NPAH and Σ6 4-ring PAH were 58 and 663 pg m−3, respectively, with 9-nitroanthracene and 2NFLT being the most concentrated amongst the targeted NPAHs. The NPAH levels observed in the marine background air are the lowest ever reported and remarkably lower, by more than 1 order of magnitude, than 1 decade before. Day–night variation of NPAHs at the continental site reflected shorter lifetime during the day, possibly because of photolysis of some NPAHs. The yields of formation of 2NFLT and 2-nitropyrene (2NPYR) in marine air seem to be close to the yields for OH-initiated photochemistry observed in laboratory experiments under high NOx conditions. Good agreement is found for the prediction of NPAH gas–particle partitioning using a multi-phase poly-parameter linear free-energy relationship. Sorption to soot is found to be less significant for gas–particle partitioning of NPAHs than for PAHs. The NPAH levels determined in the south-eastern outflow of Europe confirm intercontinental transport potential.

Star formation and polycyclic aromatic hydrocarbons in ELAIS N1 galaxies as seen by AKARI

2019 ◽  
Vol 71 (2) ◽  
Author(s):  
Tímea O Kovács ◽  
Denis Burgarella ◽  
Hidehiro Kaneda ◽  
Dániel Cs Molnár ◽  
Shinki Oyabu ◽  
...  
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Star Formation ◽  
Aromatic Hydrocarbons ◽  
Main Sequence ◽  
Compact Star ◽  
Formation Rate ◽  
Spectral Energy ◽  
Star Forming ◽  
Star Forming Regions ◽  
Polycyclic Aromatic

Abstract We have examined the relationship between star formation and polycyclic aromatic hydrocarbons (PAHs) in a variety of galaxies. PAHs are excited by the ultraviolet photons of young stars, but they are disassociated by strong UV radiation in starbursts. Therefore their emission (which is in the wavelength range covered by AKARI) can be used as a star formation tracer in main sequence galaxies. We selected our targets in the ELAIS N1 field with AKARI detections, matched them with the Herschel Point Source Catalog, and collected other publicly available photometric data. Their spectral energy distributions (SEDs) were fitted, and several parameters of the galaxies were estimated, e.g., star formation rate (SFR), stellar mass, and the fraction of PAHs compared to dust mass (qPAH), and we examined the relationships between these parameters. The final sample consisted of 48 galaxies, with redshifts from 0.04 to 2.36. The estimated qPAH values were lower on average than typical values in the literature. This could be due to various reasons, such as low metallicity, or ongoing active galactic nucleus or starburst activity. Of our sample, 83% of the objects fell in the star-forming main sequence of galaxies, while only 8% could be considered as starbursts. We found a decreasing qPAH trend with increasing AV and consequently LIR, suggesting the possible presence of compact star-forming regions. We compared the qPAH values with the known relations of the PAH luminosities, but they did not always follow the same trends (SFR, LIR), and showed only slight correlation with the PAH luminosities.

scholarly journals Spitzer spectroscopy of unusual hydrocarbons in cool radiative environments

2008 ◽  
Vol 4 (S251) ◽  
pp. 191-194 ◽  
Author(s):  
G. C. Sloan
Keyword(s):  
Polycyclic Aromatic Hydrocarbons ◽  
Aromatic Hydrocarbons ◽  
Laboratory Data ◽  
Aliphatic Hydrocarbons ◽  
Spitzer Space Telescope ◽  
Space Telescope ◽  
Radiation Fields ◽  
Polycyclic Aromatic ◽  
Class C ◽  
Larger Sample

AbstractThe Spitzer Space Telescope has discovered several objects with unusual spectra, where the emission features from polycyclic aromatic hydrocarbons (PAHs) are shifted to longer wavelengths than normally observed. Previously, only two of these class C PAH spectra had been identified. The new and larger sample reveals that PAHs emit at longer wavelengths when processed by cooler radiation fields. Limited laboratory data show that samples with mixtures of aromatic and aliphatic hydrocarbons produce emission features at longer wavelengths than purely aromatic samples. The aliphatic bonds are more fragile and would only survive in cooler radiation fields. In harsher radiation fields, the aliphatics attached to the aromatic hydrocarbons are destroyed.

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