Molecular gas and dust properties of galaxies from the Great Observatories All-sky LIRG Survey

We present IRAM-30 m Telescope 12CO and 13CO observations of a sample of 55 luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) in the local universe. This sample is a subset of the Great Observatory All-Sky LIRG Survey (GOALS), for which we use ancillary multi-wavelength data to better understand their interstellar medium and star formation properties. Fifty-three (96%) of the galaxies are detected in 12CO, and 29 (52%) are also detected in 13CO above a 3σ level. The median full width at zero intensity (FWZI) velocity of the CO line emission is 661 km s−1, and ∼54% of the galaxies show a multi-peak CO profile. Herschel photometric data is used to construct the far-IR spectral energy distribution of each galaxy, which are fit with a modified blackbody model that allows us to derive dust temperatures and masses, and infrared luminosities. We make the assumption that the gas-to-dust mass ratio of (U)LIRGs is comparable to local spiral galaxies with a similar stellar mass (i.e., gas/dust of mergers is comparable to their progenitors) to derive a CO-to-H2 conversion factor of ⟨α⟩ = 1.8−0.8+1.3 M⊙ (K km s−1 pc2)−1; such a value is comparable to that derived for (U)LIRGs based on dynamical mass arguments. We derive gas depletion times of 400 − 600 Myr for the (U)LIRGs, compared to the 1.3 Gyr for local spiral galaxies. Finally, we re-examine the relationship between the 12CO/13CO ratio and dust temperature, confirming a transition to elevated ratios in warmer systems.

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Multi-wavelength Studies of Cluster Star Forming Galaxies at z∼0.54

Proceedings of the International Astronomical Union ◽

10.1017/s1743921313001634 ◽

2012 ◽

Vol 8 (S292) ◽

pp. 337-337

Author(s):

S. M. Randriamampandry ◽

S. M. Crawford ◽

C. M. Cress ◽

K. M. Hess ◽

E. Giovannoli ◽

...

Keyword(s):

Spectral Energy Distribution ◽

Far Infrared ◽

Radio Continuum ◽

Spectral Energy ◽

Very Large Array ◽

Star Forming ◽

Bolometric Luminosity ◽

Multi Wavelength ◽

Two Parameters ◽

The Relationship

AbstractWe carry out a multi-wavelength analysis of star forming galaxies in the massive cluster MS0451.6-0305 at z∼0.54 to shed light on the evolution of the far-infrared-radio relationship in rich clusters. We have performed Spectral Energy Distribution (SED) fitting of IRAC 3.6μ, IRAC 4.5μ and MIPS 24μ photometry from Spitzer to derive the total infrared bolometric luminosity of spectroscopically confirmed cluster members with radio counterparts. The radio flux densities were measured from deep Very Large Array (VLA) radio continuum observations. The relationship between the infrared and radio luminosities for our sources show the strong correlation found between these two parameters for star forming galaxies. The far-infrared to radio luminosity ratio (qIR) values measured for these sources are comparable to those measured in low redshift clusters and indicative of an excess of radio emission.

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The Hα line emission of the Be star β Psc: the last 40 yr

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa2789 ◽

2020 ◽

Vol 501 (1) ◽

pp. 747-755

Author(s):

Ronaldo S Levenhagen ◽

Marcos P Diaz ◽

Eduardo B Amôres ◽

Nelson V Leister

Keyword(s):

Additional Data ◽

State Of The Art ◽

Spectral Energy Distribution ◽

Line Emission ◽

Spectral Energy ◽

Line Profiles ◽

Gas Density ◽

Geometric Deformation ◽

Be Star ◽

Effects Of Rotation

ABSTRACT A study on the photosphere and disc of the Be star β Psc is presented. We recover almost 40 yr of high-resolution spectroscopic observations and additional data gathered from the BeSS data base. We evaluate the photospheric parameters from the spectral energy distribution (SED) and fittings of state-of-the-art non-LTE model atmospheres to observed helium, carbon, silicon, and magnesium line profiles. Our models include the stellar geometric deformation as well as the co-latitude dependence of temperature and gravity, aiming to derive the effects of rotation on the stellar parameters. We estimate the circumstellar disc parameters from the fitting of models assuming different disc properties, namely its radius and gas density profile. The disc inclination angle i is constrained from the fittings of He i 4471 Å, Mg ii 4481 Å, C ii 4267 Å, and Si ii 4128, 4132 Å lines with gravity darkened models. Our findings, based on model fittings, suggest that during the last 40 yr, the disc radius changed within the interval 5.5 ≤ Rd ≤ 7.8 $R/R_{*}\,$, the disc base gas density within 5 × 10−13 ≤ ρ ≤ 1 × 10−12 g cm−3, while the radial power-law density index m assumed values between 2.0 and 2.3. These results are in agreement with recent works dealing with spectroscopic and interferometric measurements of this object.

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Spectral energy distribution similarity of the local galaxies and the 3.6 μm selected galaxies from the Spitzer Extended Deep Survey

Research in Astronomy and Astrophysics ◽

10.1088/1674-4527/21/10/260 ◽

2021 ◽

Vol 21 (10) ◽

pp. 260

Author(s):

Cheng Cheng ◽

Jia-Sheng Huang ◽

Hai Xu ◽

Gao-Xiang Jin ◽

Chuan He ◽

...

Keyword(s):

High Redshift ◽

Spectral Energy Distribution ◽

Mass Function ◽

Spectral Energy ◽

Energy Distributions ◽

Mid Infrared ◽

Redshift Galaxy ◽

The Galaxy ◽

Deep Survey ◽

Multi Wavelength

Abstract The Spitzer Extended Deep Survey (SEDS) as a deep and wide mid-infrared (MIR) survey project provides a sample of 500 000+ sources spreading 1.46 square degree and a depth of 26 AB mag (3σ). Combining with the previous available data, we build a PSF-matched multi-wavelength photometry catalog from u band to 8 μm. We fit the SEDS galaxies spectral energy distributions by the local galaxy templates. The results show that the SEDS galaxy can be fitted well, indicating the high redshift galaxy (z ∼ 1) shares the same templates with the local galaxies. This study would facilitate the further study of the galaxy luminosity and high redshift mass function.

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Serendipitous discovery of an “ALMA-only” galaxy at 5 < z < 6 in an ALMA 3-mm survey

Proceedings of the International Astronomical Union ◽

10.1017/s1743921320000605 ◽

2019 ◽

Vol 15 (S352) ◽

pp. 194-198

Author(s):

Christina C. Williams

Keyword(s):

Star Formation ◽

Energy Distribution ◽

Star Formation Rate ◽

High Redshift ◽

Spectral Energy Distribution ◽

Formation Rate ◽

Spectral Energy ◽

Large Contribution ◽

Massive Galaxies ◽

Multi Wavelength

AbstractWe discuss the serendipitous discovery of a dusty high-redshift galaxy in a small (8 arcmin2) ALMA 3-mm survey Williams et al. (2019). The galaxy was previously unknown and is absent from existing multi-wavelength catalogs (“ALMA-only”). Using the ALMA position as prior, we perform forced deblended photometry to constrain its spectral energy distribution. The spectral energy distribution is well described by a massive (M* = 1010.8 M⊙) and highly obscured (AV ∼ 4) galaxy at redshift z = 5.5 ± 1.1 with star formation rate ∼ 300 M⊙yr−1. Our small survey area implies an uncertain but large contribution to the cosmic star formation rate density, similar to the contribution from all ultraviolet-selected galaxies combined at this redshift. This galaxy likely traces an abundant population of massive galaxies absent from current samples of infrared-selected or sub-millimeter galaxies, but with larger space densities, higher duty cycles, and significant contribution to the cosmic star-formation rate and stellar mass densities.

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An ALMA survey of the brightest sub-millimetre sources in the SCUBA-2–COSMOS field

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/staa1345 ◽

2020 ◽

Vol 495 (3) ◽

pp. 3409-3430 ◽

Cited By ~ 3

Author(s):

J M Simpson ◽

Ian Smail ◽

U Dudzevičiūtė ◽

Y Matsuda ◽

B-C Hsieh ◽

...

Keyword(s):

Pilot Study ◽

Flux Density ◽

Luminosity Function ◽

Spectral Energy Distribution ◽

Line Emission ◽

Spectral Energy ◽

Complete Sample ◽

Photometric Redshifts ◽

Photometric Redshift ◽

Number Counts

ABSTRACT We present an ALMA study of the ∼180 brightest sources in the SCUBA-2 850-μm map of the COSMOS field from the S2COSMOS survey, as a pilot study for AS2COSMOS – a full survey of the ∼1000 sources in this field. In this pilot study, we have obtained 870-μm continuum maps of an essentially complete sample of the brightest 182 sub-millimetre sources ($S_{850\, \mu \rm m}\gt $ 6.2 mJy) in COSMOS. Our ALMA maps detect 260 sub-millimetre galaxies (SMGs) spanning a range in flux density of $S_{870\, \mu \rm m}$ = 0.7–19.2 mJy. We detect more than one SMG counterpart in 34 ± 2 per cent of sub-millimetre sources, increasing to 53 ± 8 per cent for SCUBA-2 sources brighter than $S_{850\, \mu \rm m}\gt $ 12 mJy. We estimate that approximately one-third of these SMG–SMG pairs are physically associated (with a higher rate for the brighter secondary SMGs, $S_{870\, \mu \rm m}\gtrsim$ 3 mJy), and illustrate this with the serendipitous detection of bright [C ii] 157.74-μm line emission in two SMGs, AS2COS 0001.1 and 0001.2 at z = 4.63, associated with the highest significance single-dish source. Using our source catalogue, we construct the interferometric 870-μm number counts at $S_{870\, \mu \rm m}\gt $ 6.2 mJy. We use the extensive archival data of this field to construct the multiwavelength spectral energy distribution of each AS2COSMOS SMG, and subsequently model this emission with magphys to estimate their photometric redshifts. We find a median photometric redshift for the $S_{870\, \mu \rm m}\gt $ 6.2 mJy AS2COSMOS sample of z = 2.87 ± 0.08, and clear evidence for an increase in the median redshift with 870-μm flux density suggesting strong evolution in the bright end of the 870-μm luminosity function.

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Properties of LBGs with [OIII] detection at z ∼ 3.5

Astronomy and Astrophysics ◽

10.1051/0004-6361/201935975 ◽

2019 ◽

Vol 631 ◽

pp. A123 ◽

Cited By ~ 1

Author(s):

Fang-Ting Yuan ◽

Denis Burgarella ◽

David Corre ◽

Veronique Buat ◽

Médéric Boquien ◽

...

Keyword(s):

Physical Properties ◽

Emission Line ◽

Near Infrared ◽

Spectral Energy Distribution ◽

Formation Rate ◽

Line Emission ◽

Stellar Mass ◽

Spectral Energy ◽

Emission Data ◽

The Impact

Context. Nebular emission lines are critical to measure physical properties in the ionized gas (e.g., metallicity, the star formation rate, or dust attenuation). They also account for a significant fraction of broadband fluxes, in particular at the highest redshifts, and therefore can strongly affect the determination of other physical properties, such as the stellar mass, which are crucial in shaping our understanding of galaxy formation and evolution. Aims. We investigate a sample of 51 Lyman break galaxies at 3.0 < zspec < 3.8 with detected [OIII] line emissions and estimated the physical properties of these galaxies to examine the impact of including nebular emission data in the Spectral energy distribution (SED) fitting. Methods. We used the Code Investigating GALaxy Emission (CIGALE) to fit the rest-frame ultraviolet-to-near-infrared SEDs of these galaxies and their emission line data simultaneously. We ran CIGALE with and without the nebular model or the emission line data, and compare the results to show the importance of including the nebular emission line data in the SED fitting. Results. We find that without the nebular model, the SED fitting overestimates the stellar mass due to the strong [OIII] lines that are redshifted to the Ks-band, which is consistent with previous results. The emission line data are necessary to constrain the nebular model in the SED fitting. We examine the Ks-band excess, which is mostly used to estimate the emissions of the [OIII]+Hβ lines when there is no spectral data, and we find that the estimation and observation are statistically consistent. However, the difference can reach up to more than 1 dex in some catastrophic cases, which shows the importance of obtaining spectroscopic measurements for these lines. We also estimate the equivalent width of the Hβ absorption and find it negligible compared to the Hβ emission. Conclusions. Line emission is important to constrain the nebular models and to obtain reliable estimates of the physical properties of galaxies. These data should be taken into account in the SED fitting.

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Spectral Energy Distributions of a set of H ii regions in M33 (HerM33es)

Proceedings of the International Astronomical Union ◽

10.1017/s1743921312008873 ◽

2011 ◽

Vol 7 (S284) ◽

pp. 122-124

Author(s):

Monica Relaño ◽

Simon Verley ◽

Isabel Pérez ◽

Carsten Kramer ◽

Manolis Xilouris ◽

...

Keyword(s):

Spectral Energy Distribution ◽

Morphological Type ◽

Spectral Energy ◽

H Ii Regions ◽

Energy Distributions ◽

Stellar Cluster ◽

Multi Wavelength ◽

Hα Emission ◽

Group Galaxy

AbstractWithin the framework of the HerM33es Key Project for Herschel and in combination with multi-wavelength data, we study the Spectral Energy Distribution (SED) of a set of H ii regions in the Local Group Galaxy M33. Using the Hα emission, we perform a classification of a selected H ii region sample in terms of morphology, separating the objects in filled, mixed, shell and clear shell objects. We obtain the SED for each H ii region as well as a representative SED for each class of objects. We also study the emission distribution of each band within the regions. We find different trends in the SEDs for each morphological type that are related to properties of the dust and their associated stellar cluster. The emission distribution of each band within the region is different for each morphological type of object.

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A multi-wavelength view of magnetic flaring from PMS stars

Astronomy and Astrophysics ◽

10.1051/0004-6361/201833308 ◽

2018 ◽

Vol 620 ◽

pp. A55 ◽

Cited By ~ 7

Author(s):

E. Flaccomio ◽

G. Micela ◽

S. Sciortino ◽

A. M. Cody ◽

M. G. Guarcello ◽

...

Keyword(s):

Spectral Energy Distribution ◽

Circumstellar Disks ◽

Stellar Atmospheres ◽

Spectral Energy ◽

Circumstellar Disk ◽

The Sun ◽

X Rays ◽

X Ray ◽

Multi Wavelength ◽

Pms Stars

Context. Flaring is an ubiquitous manifestation of magnetic activity in low mass stars including, of course, the Sun. Although flares, both from the Sun and from other stars, are most prominently observed in the soft X-ray band, most of the radiated energy is released at optical/UV wavelengths. In spite of decades of investigation, the physics of flares, even solar ones, is not fully understood. Even less is known about magnetic flaring in pre-main sequence (PMS) stars, at least in part because of the lack of suitable multi-wavelength data. This is unfortunate since the energetic radiation from stellar flares, which is routinely observed to be orders of magnitude greater than in solar flares, might have a significant impact on the evolution of circumstellar, planet-forming disks. Aims. We aim at improving our understanding of flares from PMS stars. Our immediate objectives are constraining the relation between flare emission at X-ray, optical, and mid-infrared (mIR) bands, inferring properties of the optically emitting region, and looking for signatures of the interaction between flares and the circumstellar environment, i.e. disks and envelopes. This information might then serve as input for detailed models of the interaction between stellar atmospheres, circumstellar disks and proto-planets. Methods. Observations of a large sample of PMS stars in the NGC 2264 star forming region were obtained in December 2011, simultaneously with three space-borne telescopes, Chandra (X-rays), CoRoT (optical), and Spitzer (mIR), as part of the “Coordinated Synoptic Investigation of NGC 2264” (CSI-NGC 2264). Shorter Chandra and CoRoT observations were also obtained in March 2008. We analyzed the lightcurves obtained during the Chandra observations (∼300 ks and ∼60 ks in 2011 and 2008, respectively), to detect X-ray flares with an optical and/or mIR counterpart. From the three datasets we then estimated basic flare properties, such as emitted energies and peak luminosities. These were then compared to constrain the spectral energy distribution of the flaring emission and the physical conditions of the emitting regions. The properties of flares from stars with and without circumstellar disks were also compared to establish any difference that might be attributed to the presence of disks. Results. Seventy-eight X-ray flares (from 65 stars) with an optical and/or mIR counterpart were detected. The optical emission of flares (both emitted energy and peak flux) is found to correlate well with, and to be significantly larger than, the X-ray emission. The slopes of the correlations suggest that the difference becomes smaller for the most powerful flares. The mIR flare emission seems to be strongly affected by the presence of a circumstellar disk: flares from stars with disks have a stronger mIR emission with respect to stars without disks. This might be attributed to either a cooler temperature of the region emitting both the optical and mIR flux or, perhaps more likely, to the reprocessing of the optical (and X-ray) flare emission by the inner circumstellar disk, providing evidence for flare-induced disk heating.

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The unique case of the AGN core of M87: a misaligned low power blazar?

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz2125 ◽

2019 ◽

Cited By ~ 4

Author(s):

M Lucchini ◽

F Krauß ◽

S Markoff

Keyword(s):

Spectral Energy Distribution ◽

Large Mass ◽

High Energy ◽

Spectral Energy ◽

Physical Parameters ◽

Zone Model ◽

Multi Wavelength ◽

General Relativistic ◽

Unique Source ◽

High Energy Emission

Abstract M87 hosts one of the closest jetted active galactic nucleus (AGN) to Earth. Thanks to its vicinity and to the large mass of is central black hole, M87 is the only source in which the jet can be directly imaged down to near-event horizon scales with radio very large baseline interferometry (VLBI). This property makes M87 a unique source to isolate and study jet launching, acceleration and collimation. In this paper we employ a multi-zone model designed as a parametrisation of general relativistic magneto-hydrodynamics (GRMHD); for the first time we reproduce the jet’s observed shape and multi-wavelength spectral energy distribution (SED) simultaneously. We find strong constraints on key physical parameters of the jet, such as the location of particle acceleration and the kinetic power. However, we under-predict the (unresolved) γ-ray flux of the source, implying that the high-energy emission does not originate in the magnetically-dominated inner jet regions. Our results have important implications both for comparisons of GRMHD simulations with observations, and for unified models of AGN classes.

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The ‘Red Radio Ring’: ionized and molecular gas in a starburst/active galactic nucleus at z ∼ 2.55

Monthly Notices of the Royal Astronomical Society ◽

10.1093/mnras/stz1740 ◽

2019 ◽

Vol 488 (2) ◽

pp. 1489-1500 ◽

Cited By ~ 2

Author(s):

Kevin C Harrington ◽

A Vishwas ◽

A Weiß ◽

B Magnelli ◽

L Grassitelli ◽

...

Keyword(s):

Fine Structure ◽

Spectral Energy Distribution ◽

Formation Rate ◽

Line Emission ◽

Far Infrared ◽

Spectral Energy ◽

Molecular Gas ◽

H Ii Regions ◽

Galaxy Assembly ◽

Dust Attenuation

ABSTRACT We report the detection of the far-infrared (FIR) fine-structure line of singly ionized nitrogen, [N ii] 205 $\mu$m , within the peak epoch of galaxy assembly, from a strongly lensed galaxy, hereafter ‘The Red Radio Ring’; the RRR, at z = 2.55. We combine new observations of the ground-state and mid-J transitions of CO (Jup = 1, 5, 8), and the FIR spectral energy distribution (SED), to explore the multiphase interstellar medium (ISM) properties of the RRR. All line profiles suggest that the H ii regions, traced by [N ii] 205 $\mu$m , and the (diffuse and dense) molecular gas, traced by CO, are cospatial when averaged over kpc-sized regions. Using its mid-IR-to-millimetre (mm) SED, we derive a non-negligible dust attenuation of the [N ii] 205 $\mu$m line emission. Assuming a uniform dust screen approximation results a mean molecular gas column density >1024 cm−2, with a molecular gas-to-dust mass ratio of 100. It is clear that dust attenuation corrections should be accounted for when studying FIR fine-structure lines in such systems. The attenuation corrected ratio of $L_{\rm N\,{\small II}205} / L_{\rm IR(8\!-\!1000\, \mu m)} = 2.7 \times 10^{-4}$ is consistent with the dispersion of local and z > 4 SFGs. We find that the lower limit, [N ii] 205 $\mu$m -based star formation rate (SFR) is less than the IR-derived SFR by a factor of 4. Finally, the dust SED, CO line SED, and $L_{\rm N\,{\small II}205}$ line-to-IR luminosity ratio of the RRR is consistent with a starburst-powered ISM.

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