scholarly journals The ALPINE-ALMA [CII] survey

2020 ◽  
Vol 643 ◽  
pp. A7
Author(s):  
M. Ginolfi ◽  
G. C. Jones ◽  
M. Béthermin ◽  
A. Faisst ◽  
B. C. Lemaux ◽  
...  
Keyword(s):  
Decomposition Analysis ◽  
Far Infrared ◽  
Ancillary Data ◽  
Interstellar Gas ◽  
Star Forming ◽  
The Galaxy ◽  
Multi Wavelength ◽  
Major Merger ◽  
Continuum Data ◽  
The Individual

We present ALMA observations of a merging system at z ∼ 4.57, observed as a part of the ALMA Large Program to INvestigate [CII] at Early times (ALPINE) survey. Combining ALMA [CII]158 μm and far-infrared continuum data with multi-wavelength ancillary data, we find that the system is composed of two massive (M⋆ ≳ 1010 M⊙) star-forming galaxies experiencing a major merger (stellar mass ratio rmass ≳ 0.9) at close spatial (∼13 kpc; projected) and velocity (Δv <  300 km s−1) separations, and two additional faint narrow [CII]-emitting satellites. The overall system belongs to a larger scale protocluster environment and is coincident to one of its overdensity peaks. Additionally, ALMA reveals the presence of [CII] emission arising from a circumgalactic gas structure, extending up to a diameter-scale of ∼30 kpc. Our morpho-spectral decomposition analysis shows that about 50% of the total flux resides between the individual galaxy components, in a metal-enriched gaseous envelope characterised by a disturbed morphology and complex kinematics. Similarly to observations of shock-excited [CII] emitted from tidal tails in local groups, our results can be interpreted as a possible signature of interstellar gas stripped by strong gravitational interactions, with a possible contribution from material ejected by galactic outflows and emission triggered by star formation in small faint satellites. Our findings suggest that mergers could be an efficient mechanism of gas mixing in the circumgalactic medium around high-z galaxies, and thus play a key role in the galaxy baryon cycle at early epochs.

scholarly journals Accurate dust temperature determination in a z = 7.13 galaxy

2021 ◽  
Author(s):  
Tom J L C Bakx ◽  
Laura Sommovigo ◽  
Stefano Carniani ◽  
Andrea Ferrara ◽  
Hollis B Akins ◽  
...  
Keyword(s):  
Formation Rate ◽  
Far Infrared ◽  
Spectral Energy ◽  
Ancillary Data ◽  
Star Forming ◽  
Dust Temperature ◽  
Density Fitting ◽  
Mass Estimate ◽  
Continuum Data ◽  
First Time

Abstract We report ALMA Band 9 continuum observations of the normal, dusty star-forming galaxy A1689-zD1 at z = 7.13, resulting in a ∼4.6 σ detection at 702 GHz. For the first time these observations probe the far-infrared (FIR) spectrum shortward of the emission peak of a galaxy in the Epoch of Reionization (EoR). Together with ancillary data from earlier works, we derive the dust temperature, Td, and mass, Md, of A1689-zD1 using both traditional modified blackbody spectral energy density fitting, and a new method that relies only on the [C ii] 158 μm line and underlying continuum data. The two methods give $T_{\rm d} = (42^{+13}_{-7}, 40^{+13}_{-7}$) K, and $M_{\rm d} = (1.7^{+1.3}_{-0.7}, 2.0^{+1.8}_{-1.0})\, \times {}\, 10^{7} \, M_{\odot }$. Band 9 observations improve the accuracy of the dust temperature (mass) estimate by ∼50 per cent (6 times). The derived temperatures confirm the reported increasing Td-redshift trend between z = 0 and 8; the dust mass is consistent with a supernova origin. Although A1689-zD1 is a normal UV-selected galaxy, our results, implying that ∼85 per cent of its star formation rate is obscured, underline the non-negligible effects of dust in EoR galaxies.

scholarly journals The role of AGN activity in the building up of the BCG at z ∼ 1.6

2019 ◽  
Vol 15 (S356) ◽  
pp. 280-284
Author(s):  
Angela Bongiorno ◽  
Andrea Travascio
Keyword(s):  
Galaxy Cluster ◽  
Cluster Galaxy ◽  
X Ray ◽  
Groups Of Galaxies ◽  
Star Forming ◽  
The Core ◽  
The Galaxy ◽  
Multi Wavelength

AbstractXDCPJ0044.0-2033 is one of the most massive galaxy cluster at z ∼1.6, for which a wealth of multi-wavelength photometric and spectroscopic data have been collected during the last years. I have reported on the properties of the galaxy members in the very central region (∼ 70kpc × 70kpc) of the cluster, derived through deep HST photometry, SINFONI and KMOS IFU spectroscopy, together with Chandra X-ray, ALMA and JVLA radio data.In the core of the cluster, we have identified two groups of galaxies (Complex A and Complex B), seven of them confirmed to be cluster members, with signatures of ongoing merging. These galaxies show perturbed morphologies and, three of them show signs of AGN activity. In particular, two of them, located at the center of each complex, have been found to host luminous, obscured and highly accreting AGN (λ = 0.4−0.6) exhibiting broad Hα line. Moreover, a third optically obscured type-2 AGN, has been discovered through BPT diagram in Complex A. The AGN at the center of Complex B is detected in X-ray while the other two, and their companions, are spatially related to radio emission. The three AGN provide one of the closest AGN triple at z > 1 revealed so far with a minimum (maximum) projected distance of 10 kpc (40 kpc). The discovery of multiple AGN activity in a highly star-forming region associated to the crowded core of a galaxy cluster at z ∼ 1.6, suggests that these processes have a key role in shaping the nascent Brightest Cluster Galaxy, observed at the center of local clusters. According to our data, all galaxies in the core of XDCPJ0044.0-2033 could form a BCG of M* ∼ 1012Mȯ hosting a BH of 2 × 108−109Mȯ, in a time scale of the order of 2.5 Gyrs.

scholarly journals Giant Molecular Clouds in the Galaxy: The Massachusetts-Stony Brook CO Galactic Plane Survey

1987 ◽  
Vol 115 ◽  
pp. 499-499 ◽  
Author(s):  
P. M. Solomon
Keyword(s):  
Molecular Clouds ◽  
Galactic Plane ◽  
Far Infrared ◽  
Formation Mechanisms ◽  
H Ii Regions ◽  
Giant Molecular Clouds ◽  
Star Forming ◽  
The Galaxy ◽  
Two Populations ◽  
Spiral Arm

The CO Galactic Plane Survey consists of 40,572 spectral line observations in the region between 1 = 8° to 90° and b = −1°.05 to +1°.05 spaced every 3 arc minutes, carried out with the FCRAO 14-m antenna. The velocity coverage from −100 to +200 km/s includes emission from all galactic radii. This high resolution survey was designed to observe and identify essentially all molecular clouds or cloud components larger than 10 parsecs in the inner galaxy. There are two populations of molecular clouds which separate according to temperature. The warm clouds are closely associated with H II regions, exhibit a non-axisymmetric galactic distribution and are a spiral arm population. The cold clouds are a disk population, are not confined to any patterns in longitude-velocity space and must be widespread in the galaxy both in and out of spiral arms. The correlation between far infrared luminosities from IRAS, and molecular masses from CO is utilized to determine a luminosity to mass ratio for the clouds. A face-on picture of the galaxy locating the warm population is presented, showing ring like or spiral arm features at R ∼ 5, 7.5 and 9 kpc. The cloud size and mass spectrum will be discussed and evidence presented showing the presence of clusters of giant molecular clouds with masses of 106 to 107 M⊙. The two populations of clouds probably have different star forming luminosity functions. The implication of the two populations for star formation mechanisms will be discussed.

scholarly journals Multi-wavelength de-blended Herschel view of the statistical properties of dusty star-forming galaxies across cosmic time

2019 ◽  
Vol 624 ◽  
pp. A98 ◽  
Author(s):  
L. Wang ◽  
W. J. Pearson ◽  
W. Cowley ◽  
J. W. Trayford ◽  
M. Béthermin ◽  
...  
Keyword(s):  
Star Formation ◽  
Dynamic Range ◽  
Transition Period ◽  
Formation Rate ◽  
Cosmic Time ◽  
Far Infrared ◽  
Statistical Properties ◽  
Star Forming ◽  
Multi Wavelength ◽  
Number Counts

Aims. We study the statistical properties of dusty star-forming galaxies across cosmic time, such as their number counts, luminosity functions (LF), and the dust-obscured star formation rate density (SFRD). Methods. We used the most recent de-blended Herschel catalogue in the COSMOS field to measure the number counts and LFs at far-infrared (FIR) and sub-millimetre (sub-mm) wavelengths. The de-blended catalogue was generated by combining the Bayesian source extraction tool XID+ and an informative prior derived from the associated deep multi-wavelength photometric data. Results. Through our de-confusion technique and based on the deep multi-wavelength photometric information, we are able to achieve more accurate measurements while at the same time probing roughly ten times below the Herschel confusion limit. Our number counts at 250 μm agree well with previous Herschel studies. However, our counts at 350 and 500 μm are below previous Herschel results because previous Herschel studies suffered from source confusion and blending issues. Our number counts at 450 and 870 μm show excellent agreement with previous determinations derived from single-dish and interferometric observations. Our measurements of the LF at 250 μm and the total IR LF agree well with previous results in the overlapping redshift and luminosity range. The increased dynamic range of our measurements allows us to better measure the faint-end of the LF and measure the dust-obscured SFRD out to z ∼ 6. We find that the fraction of obscured star formation activity is at its highest (>80%) around z ∼ 1. We do not find a shift of balance between z ∼ 3 and z ∼ 4 in the SFRD from being dominated by unobscured star formation at higher redshift to obscured star formation at lower redshift. However, we do find 3 <  z <  4 to be an interesting transition period as the portion of the total SFRD that is obscured by dust is significantly lower at higher redshifts.

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 Constraints on Far-Infrared Source Counts in the Lockman Hole using a Power Spectrum Analysis

2001 ◽  
Vol 204 ◽  
pp. 301-301
Author(s):  
H. Matsuhara ◽  
K. Kawara ◽  
Y. Sofue ◽  
Y. Taniguchi ◽  
Y. Sato ◽  
...  
Keyword(s):  
Background Radiation ◽  
Power Spectra ◽  
Far Infrared ◽  
Infrared Space Observatory ◽  
Infrared Source ◽  
Star Forming ◽  
The Galaxy ◽  
Galaxy Count ◽  
Infrared Background ◽  
Lockman Hole

We present the characteristics of far-infrared (FIR) brightness fluctuations at 90 μm and 170 μm in the Lockman Hole, which were surveyed with the ISOPHOT instrument aboard the Infrared Space Observatory (ISO), and give constraints on the galaxy number counts down to 30 mJy at 90 μm and 50 mJy at 170 μm. The fluctuation power spectra of the FIR images are not dominated by IR cirrus, and are instead most likely due to star-forming galaxies. This analysis indicates the existence of strong evolution in the counts. Especially at 90 μm, the source density is much larger than that expected from the currently available galaxy count models. The galaxies responsible for the fluctuations also significantly contribute to the cosmic infrared background radiation recently derived from an analysis of the COBE data.

scholarly journals The Diffuse Ionised Gas in NGC 4449

1998 ◽  
Vol 15 (1) ◽  
pp. 103-105 ◽  
Author(s):  
C. Muñoz-Tuñón ◽  
O. Fuentes-Masip ◽  
H. O. Castañeda
Keyword(s):  
Large Population ◽  
Star Forming ◽  
Star Forming Regions ◽  
La Palma ◽  
Total Luminosity ◽  
Spatial Coverage ◽  
The Galaxy ◽  
Uv Photons ◽  
Set Up ◽  
The Individual

AbstractIt is now well established that there is a diffuse ionised medium which extends far beyond the disks of spirals. The mechanism responsible for the ionisation is still an issue of debate, and the method of measuring the total luminosity, independently of the observational set-up, has to be defined. Here we analyse the case of the Magellanic irregular NGC 4449, using Fabry–Perot bidimensional mapping of the Hα emission line, at the 4·2 m William Herschel Telescope (WHT) telescope on La Palma, Canary Islands. The total spatial coverage of 80×80 arcsec2 allows most of the star forming regions to be sampled at 0·26 arcsec/pixel spatial resolution. Using 3D spectroscopy, it is possible to define the individual star-forming regions and to produce a luminosity versus size diagram. This can be used to estimate directly the number of photons leaking out from those regions exceeding the thickness of the galactic disc. In the case of NGC 4449 it is shown that the large population of GEHRs can be the source of UV photons ionising the diffuse ionised gas (DIG) of the galaxy, and the logL–R diagram can be used to quantify the number of photons leaking out of the material surrounding the star forming regions. In the case of NGC 4449 it is found that 54% of the total luminosity of the giant star-forming regions is lost to the DIG. This implies a contribution of 3·12×1040 erg s−1 (1 erg s−1 = 10−7 J s−1) which amounts to 30% of the galaxy total Hα luminosity.

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 Resolving a dusty, star-forming SHiZELS galaxy at z = 2.2 with HST, ALMA and SINFONI on kiloparsec scales

2021 ◽  
Author(s):  
R K Cochrane ◽  
P N Best ◽  
I Smail ◽  
E Ibar ◽  
C Cheng ◽  
...  
Keyword(s):  
Star Formation ◽  
Emission Line ◽  
Rest Frame ◽  
Far Infrared ◽  
Radio Continuum ◽  
Continuum Emission ◽  
Star Forming ◽  
Alpha Emission ◽  
The Galaxy ◽  
Dust Distribution

Abstract We present ∼0.15″ spatial resolution imaging of SHiZELS-14, a massive ($M_{*}\sim 10^{11}\, \rm {M_{\odot }}$), dusty, star-forming galaxy at z = 2.24. Our rest-frame $\sim 1\, \rm {kpc}$-scale, matched-resolution data comprise four different widely used tracers of star formation: the $\rm {H}\alpha$ emission line (from SINFONI/VLT), rest-frame UV continuum (from HST F606W imaging), the rest-frame far-infrared (from ALMA), and the radio continuum (from JVLA). Although originally identified by its modest $\rm {H}\alpha$ emission line flux, SHiZELS-14 appears to be a vigorously star-forming ($\rm {SFR}\sim 1000\, \rm {M_{\odot }\, yr^{-1}}$) example of a submillimeter galaxy, probably undergoing a merger. SHiZELS-14 displays a compact, dusty central starburst, as well as extended emission in $\rm {H}\alpha$ and the rest-frame optical and FIR. The UV emission is spatially offset from the peak of the dust continuum emission, and appears to trace holes in the dust distribution. We find that the dust attenuation varies across the spatial extent of the galaxy, reaching a peak of at least AHα ∼ 5 in the most dusty regions, although the extinction in the central starburst is likely to be much higher. Global star-formation rates inferred using standard calibrations for the different tracers vary from $\sim 10\!-\!1000\, \rm {M_{\odot }\, yr^{-1}}$, and are particularly discrepant in the galaxy’s dusty centre. This galaxy highlights the biased view of the evolution of star-forming galaxies provided by shorter wavelength data.

scholarly journals Search for gas accretion imprints in voids: II. The galaxy Ark 18 as a result of a dwarf-dwarf merger

2021 ◽  
Author(s):  
Evgeniya S Egorova ◽  
Oleg V Egorov ◽  
Alexei V Moiseev ◽  
Anna S Saburova ◽  
Kirill A Grishin ◽  
...  
Keyword(s):  
Complex Structure ◽  
Disc Galaxy ◽  
Star Forming ◽  
Galaxy Type ◽  
The Galaxy ◽  
Depth Study ◽  
Multi Wavelength ◽  
Low Mass ◽  
Formation And Evolution ◽  
Gas Accretion

Abstract The low-mass low-surface brightness (LSB) disc galaxy Arakelian 18 (Ark 18) resides in the Eridanus void and because of its isolation represents an ideal case to study the formation and evolution mechanisms of such a galaxy type. Its complex structure consists of an extended blue LSB disc and a bright central elliptically-shaped part hosting a massive off-centered star-forming clump. We present the in-depth study of Ark 18 based on observations with the SCORPIO-2 long-slit spectrograph and a scanning Fabry-Perot interferometer at the Russian 6-m telescope complemented by archival multi-wavelength images and SDSS spectra. Ark 18 appears to be a dark matter dominated gas-rich galaxy without a radial metallicity gradient. The observed velocity field of the ionised gas is well described by two circularly rotating components moderately inclined with respect to each other and a possible warp in the outer disc. We estimated the age of young stellar population in the galaxy centre to be ∼140 Myr, while the brightest star-forming clump appears to be much younger. We conclude that the LSB disc is likely the result of a dwarf–dwarf merger with a stellar mass ratio of the components at least ∼5:1 that occurred earlier than 300 Myr ago. The brightest star forming clump was likely formed later by accretion of a gas cloud.

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