Far-infrared and CO observations of CEP F - Implications for star formation in Cepheus OB3

1983 ◽  
Vol 88 ◽  
pp. 1236 ◽  
Author(s):  
A. I. Sargent ◽  
R. J. van Duinen ◽  
H. L. Nordh ◽  
C. V. M. Fridlund ◽  
J. W. G. Aalders ◽  
...  
Keyword(s):  
Star Formation ◽  
Far Infrared ◽  
Co Observations

scholarly journals CO Observations of Bright IRAS Galaxies

1987 ◽  
Vol 115 ◽  
pp. 653-653
Author(s):  
D. B. Sanders
Keyword(s):  
Star Formation ◽  
Molecular Clouds ◽  
Formation Rate ◽  
Far Infrared ◽  
Molecular Gas ◽  
Infrared Excess ◽  
Luminous Galaxies ◽  
Be Star ◽  
Co Emission ◽  
Co Observations

CO emission has been detected from 75 bright infrared galaxies with CZ = 2 000 – 16 000 km/s. These include the most distant and the most luminous galaxies (Arp 55, IR 1713+63) yet detected in CO. All of these galaxies are rich in molecular gas with Mtotal (H2) = 2 × 109 −6x1010 M⊙, and they have a strong far-infrared excess, with LFIR/LB = 2-40 and LFIR (40-400μ) = 1010 – 3 × 1012 L⊙. The primary luminosity source appears to be star formation in molecular clouds. A strong correlation is found between the FIR and 21-cm continuum flux, implying that the IMF is independent of the star formation rate. The ratio LFIR/M(H2) provides a measure of the current rate of star-formation, which is found to be a factor 3-20 larger in these galaxies than for the ensemble of molecular clouds in the Milky Way. VLA maps plus a few high resolution (14″-30″) CO (1-0) and CO (2-1) maps suggest that most of the luminosity comes from core regions 1-3 kpc in size. The abnormal concentration of molecular gas in these galactic cores is presumably the result of a collision or strong interaction with a nearby companion.

Tracing young SMBHs in the dusty distant universe – a Chandra view of DOGs

2020 ◽  
Vol 15 (S359) ◽  
pp. 17-21
Author(s):  
Karín Menéndez-Delmestre ◽  
Laurie Riguccini ◽  
Ezequiel Treister
Keyword(s):  
Star Formation ◽  
Main Sequence ◽  
Far Infrared ◽  
Host Galaxy ◽  
X Ray ◽  
Star Forming ◽  
Near Ir ◽  
X Ray Imaging ◽  
Combined Use ◽  
Dusty Galaxies

AbstractThe coexistence of star formation and AGN activity has geared much attention to dusty galaxies at high redshifts, in the interest of understanding the origin of the Magorrian relation observed locally, where the mass of the stellar bulk in a galaxy appears to be tied to the mass of the underlying supermassive black hole. We exploit the combined use of far-infrared (IR) Herschel data and deep Chandra ˜160 ksec depth X-ray imaging of the COSMOS field to probe for AGN signatures in a large sample of >100 Dust-Obscured Galaxies (DOGs). Only a handful (˜20%) present individual X-ray detections pointing to the presence of significant AGN activity, while X-ray stacking analysis on the X-ray undetected DOGs points to a mix between AGN activity and star formation. Together, they are typically found on the main sequence of star-forming galaxies or below it, suggesting that they are either still undergoing significant build up of the stellar bulk or have started quenching. We find only ˜30% (6) Compton-thick AGN candidates (NH > 1024 cm–2), which is the same frequency found within other soft- and hard-X-ray selected AGN populations. This suggests that the large column densities responsible for the obscuration in Compton-thick AGNs must be nuclear and have little to do with the dust obscuration of the host galaxy. We find that DOGs identified to have an AGN share similar near-IR and mid-to-far-IR colors, independently of whether they are individually detected or not in the X-ray. The main difference between the X-ray detected and the X-ray undetected populations appears to be in their redshift distributions, with the X-ray undetected ones being typically found at larger distances. This strongly underlines the critical need for multiwavelength studies in order to obtain a more complete census of the obscured AGN population out to higher redshifts. For more details, we refer the reader to Riguccini et al. (2019).

scholarly journals Molecular gas in the Herschel-selected strongly lensed submillimeter galaxies at z ~ 2–4 as probed by multi-J CO lines

2017 ◽  
Vol 608 ◽  
pp. A144 ◽  
Author(s):  
C. Yang ◽  
A. Omont ◽  
A. Beelen ◽  
Y. Gao ◽  
P. van der Werf ◽  
...  
Keyword(s):  
Star Formation ◽  
High Redshift ◽  
Line Emission ◽  
Far Infrared ◽  
Molecular Gas ◽  
Kinetic Temperature ◽  
Large Area ◽  
Line Energy ◽  
Submillimeter Galaxies ◽  
Dust Mass

We present the IRAM-30 m observations of multiple-J CO (Jup mostly from 3 up to 8) and [C I](3P2 → 3P1) ([C I](2–1) hereafter) line emission in a sample of redshift ~2–4 submillimeter galaxies (SMGs). These SMGs are selected among the brightest-lensed galaxies discovered in the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS). Forty-seven CO lines and 7 [C I](2–1) lines have been detected in 15 lensed SMGs. A non-negligible effect of differential lensing is found for the CO emission lines, which could have caused significant underestimations of the linewidths, and hence of the dynamical masses. The CO spectral line energy distributions (SLEDs), peaking around Jup ~ 5–7, are found to be similar to those of the local starburst-dominated ultra-luminous infrared galaxies and of the previously studied SMGs. After correcting for lensing amplification, we derived the global properties of the bulk of molecular gas in the SMGs using non-LTE radiative transfer modelling, such as the molecular gas density nH2 ~ 102.5–104.1 cm-3 and the kinetic temperature Tk  ~ 20–750 K. The gas thermal pressure Pth ranging from~105 K cm-3 to 106 K cm-3 is found to be correlated with star formation efficiency. Further decomposing the CO SLEDs into two excitation components, we find a low-excitation component with nH2 ~ 102.8–104.6 cm-3 and Tk  ~ 20–30 K, which is less correlated with star formation, and a high-excitation one (nH2 ~ 102.7–104.2 cm-3, Tk  ~ 60–400 K) which is tightly related to the on-going star-forming activity. Additionally, tight linear correlations between the far-infrared and CO line luminosities have been confirmed for the Jup ≥ 5 CO lines of these SMGs, implying that these CO lines are good tracers of star formation. The [C I](2–1) lines follow the tight linear correlation between the luminosities of the [C I](2–1) and the CO(1–0) line found in local starbursts, indicating that [C I] lines could serve as good total molecular gas mass tracers for high-redshift SMGs as well. The total mass of the molecular gas reservoir, (1–30) × 1010M⊙, derived based on the CO(3–2) fluxes and αCO(1–0) = 0.8 M⊙ ( K km s-1 pc2)-1, suggests a typical molecular gas depletion time tdep ~ 20–100 Myr and a gas to dust mass ratio δGDR ~ 30–100 with ~20%–60% uncertainty for the SMGs. The ratio between CO line luminosity and the dust mass L′CO/Mdust appears to be slowly increasing with redshift for high-redshift SMGs, which need to be further confirmed by a more complete SMG sample at various redshifts. Finally, through comparing the linewidth of CO and H2O lines, we find that they agree well in almost all our SMGs, confirming that the emitting regions of the CO and H2O lines are co-spatially located.

scholarly journals Far-Infrared Emission from Clumpy Irregular Galaxies

1987 ◽  
Vol 115 ◽  
pp. 647-647
Author(s):  
U. Klein ◽  
J. Heidmann ◽  
R. Wielebinski ◽  
E. Wunderlich
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Hubble Constant ◽  
Far Infrared ◽  
Hii Regions ◽  
Infrared Emission ◽  
Star Forming ◽  
Irregular Galaxies

The four clumpy irregular galaxies Mkr 8, 296,297 and 325 have been observed by IRAS. All galaxies have been detected in at least two of the four detector bands. The ratios of the 100 to 60-m flux densities are comparable to those of HII regions or violently star forming galaxies. The average star formation rate in clumpy irregular galaxies is of the order of a few solar masses per year (based on their average far-infrared luminosity and a Hubble constant of 75 km s−1 Mpc−1.

scholarly journals THE CALIBRATION OF MONOCHROMATIC FAR-INFRARED STAR FORMATION RATE INDICATORS

2010 ◽  
Vol 714 (2) ◽  
pp. 1256-1279 ◽  
Author(s):  
D. Calzetti ◽  
S.-Y. Wu ◽  
S. Hong ◽  
R. C. Kennicutt ◽  
J. C. Lee ◽  
...  
Keyword(s):  
Star Formation ◽  
Star Formation Rate ◽  
Formation Rate ◽  
Far Infrared ◽  
Infrared Star

scholarly journals Radio Loud Far-Infrared Galaxies

1990 ◽  
Vol 124 ◽  
pp. 309-314 ◽  
Author(s):  
Arjun Dey ◽  
Wil van Breugel ◽  
Joseph C. Shields
Keyword(s):  
Star Formation ◽  
Radio Emission ◽  
Point Source ◽  
Optical Imaging ◽  
Radio Galaxy ◽  
Far Infrared ◽  
Infrared Galaxies ◽  
Galaxy Interactions ◽  
First Results ◽  
Radio Survey

AbstractWe present the first results of a multiwavelength study of IRAS galaxies with excess radio emission. The sample was selected by cross-correlating the IRAS Faint Source Survey (for |b| ≥ 50°) and the Point Source Catalogue (for 10° < |b| < 50°) with the Texas radio survey. Recent optical (imaging and spectroscopic) and radio (VLA) observations are discussed. These observations will be used to investigate possible connections between radio galaxy activity, star formation and galaxy interactions.

scholarly journals Statistical Properties of the Mid and Far IR Emission in Mixed Morphology (E+S) Pairs of Galaxies

2000 ◽  
Vol 174 ◽  
pp. 203-204
Author(s):  
H. M. Hernández Toledo ◽  
D. Dultzin-Hacyan ◽  
J. W. Sulentic
Keyword(s):  
Star Formation ◽  
Formation Rate ◽  
Control Sample ◽  
Far Infrared ◽  
High Mass ◽  
Clear Correlation ◽  
Detailed Statistical Analysis ◽  
Account Information ◽  
Ir Emission ◽  
Parametric Estimate

We report the results of a detailed statistical analysis of the Mid and Far IR (MIR/FIR) emission properties in a mixed morphology (E+S) sample of galaxy pairs from the Karachentsev (1972) Catalogue. The sample is large and diverse enough (≃ 130 pairs) to permit discrimination of pairs by morphological types and interaction classes. It samples a large enough volume to enable a non-parametric estimate of a Far-Infrared Luminosity Function (FIRLF). We find average factors of 3 and 5 enhancement in FIR and 25μm luminosities of the late-type pair components relative to an isolated galaxy control sample from Karachentseva (1973) Catalogue. This is interpreted as the MIR/FIR signature of the link between interaction and star formation. Although the spirals in (E+S) pairs fail to show a trend towards higher FIR luminosity with decreasing companion separation, a high-order comparison that takes into account information on the interaction classes, morphological types and the HI content suggests that:•a clear correlation between the IR luminosities and interaction classes is present suggesting that a subsample of the (E+S) pairs is more closely related to recent events of star formation,•the ratio of present to past star formation (as measured by the IR luminosities scaled to LB luminosity), increases measurably along the sequence Sa-Sc in paired spirals,•no Hɪ depletion in the star formation-enhanced spirals in mixed pairs is found, and•the high mass (M ≥ 10 M⊙) star formation rate (SFR) in paired Sc spirals is higher than that of the isolated Sc’s by a factor ~ 2 – 3.

scholarly journals ALMA witnesses the assembly of first galaxies

2019 ◽  
Vol 15 (S352) ◽  
pp. 27-32
Author(s):  
Stefano Carniani
Keyword(s):  
Star Formation ◽  
Physical Properties ◽  
Rest Frame ◽  
Near Infrared ◽  
Far Infrared ◽  
Star Forming ◽  
Surrounding Environment ◽  
Infrared Surveys ◽  
Formation And Evolution ◽  
First Galaxies

AbstractCharacterising primeval galaxies entails the challenging goal of observing galaxies with modest star formation rates (SFR < 100 Mȯyr−1) and approaching the beginning of the reionisation epoch (z > 6). To date a large number of primeval galaxies have been identified thanks to deep near-infrared surveys. However, to further our understanding on the formation and evolution of such primeval objects, we must investigate their nature and physical properties through multi-band spectroscopic observations. Information on dust content, metallicity, interactions with the surrounding environment, and outflows can be obtained with ALMA observations of far-infrared (FIR) lines such as the [Cii] at 158 μm and [Oiii] at 88 μm. Here, we, thus, discuss the recent results unveiled by ALMA observations and present new [Cii] observations of BDF-3299, a star-forming galaxy at z = 7.1 showing a spatial and spectral offset between the rest-frame UV and the FIR lines emission.

scholarly journals The Evolution of Giant Molecular Clouds

1980 ◽  
Vol 87 ◽  
pp. 137-149 ◽  
Author(s):  
Colin Norman ◽  
Joseph Silk
Keyword(s):  
Spatial Distribution ◽  
Star Formation ◽  
Molecular Clouds ◽  
Supernova Remnants ◽  
Density Wave ◽  
Collective Effects ◽  
Giant Molecular Clouds ◽  
Spiral Density Wave ◽  
External Galaxies ◽  
Co Observations

We discuss the origin, lifetime, destruction, spatial distribution and relation to star formation of giant molecular clouds. A coagulation model including the effects of spiral density wave shocks is described. We explore implications for CO observations of external galaxies. The collective effects of OB star winds and supernova remnants in disrupting clouds are considered.

VLA Observations of a Sample of Low-Brightness 6.7 GHz Methanol Masers

2017 ◽  
Vol 13 (S336) ◽  
pp. 311-312
Author(s):  
Luca Olmi ◽  
Esteban D. Araya ◽  
Jason Armstrong
Keyword(s):  
New Mexico ◽  
Star Formation ◽  
Far Infrared ◽  
Large Array ◽  
Very Large Array ◽  
Early Stages ◽  
Methanol Masers ◽  
Infrared Sources ◽  
Massive Cores

AbstractIn 2014 we conducted a survey for 6.7 GHz methanol masers with the Arecibo Telescope toward far infrared sources selected from the Hi-GAL catalog of massive cores. We found a number of sources with weak 6.7 GHz methanol masers, possibly indicating regions in early stages of star formation. Here we describe the results of follow-up observations that were conducted with the Very Large Array in New Mexico to characterize this new population of “weak” 6.7 GHz methanol masers.

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