scholarly journals z > 4 low luminosity dusty galaxy candidates in the Frontier Fields A2744, AS1063 and A370

2015 ◽  
Vol 11 (A29B) ◽  
pp. 818-819
Author(s):  
Frédéric Boone ◽  
Daniel Schaerer ◽  
Johan Richard ◽  
Benjamin Clément ◽  
Eiichi Egami ◽  
...  
Keyword(s):  
Star Formation ◽  
High Redshift ◽  
Multiple Sources ◽  
Multiple Images ◽  
Dust Temperature ◽  
Very High ◽  
Intrinsic Luminosity

AbstractWe have conducted a LABOCA 870 μm follow-up of ten massive lensing clusters of the Herschel Lensing Survey (HLS, Egami et al. 2010) aiming at unveiling the yet hidden part of dusty star formation in the distant Universe. Among these clusters, A2744 and AS1063 are part of the Frontier Fields HST program. We also obtained 2 mm bolometer observations of A2744 and A370 with the GISMO array at the IRAM 30 m. We detected sources that are undetected with Herschel (PACS and SPIRE) implying either a very high redshift (z > 4) or a very low dust temperature (T<25 K). Their flux also imply a low intrinsic luminosity, LFIR < 1012L⊙. Some of them are extended and could correspond to multiple sources or to multiple images of a lensed source. Substructures in the Sunyaev-Zeldovich effect could also contribute this very red submm emission. An ALMA program is ongoing to unveil the nature of these sources.

scholarly journals Strongly Lensed Supernovae in Well-Studied Galaxy Clusters with the Vera C. Rubin Observatory

Symmetry ◽  
2020 ◽  
Vol 12 (12) ◽  
pp. 1966
Author(s):  
Tanja Petrushevska
Keyword(s):  
Galaxy Clusters ◽  
High Redshift ◽  
Cosmological Parameters ◽  
Hubble Constant ◽  
Multiple Images ◽  
Strong Lensing ◽  
Type Ia ◽  
Ia Supernovae ◽  
Massive Galaxy

Strong lensing by galaxy clusters can be used to significantly expand the survey reach, thus allowing observation of magnified high-redshift supernovae that otherwise would remain undetected. Strong lensing can also provide multiple images of the galaxies that lie behind the clusters. Detection of strongly lensed Type Ia supernovae (SNe Ia) is especially useful because of their standardizable brightness, as they can be used to improve either cluster lensing models or independent measurements of cosmological parameters. The cosmological parameter, the Hubble constant, is of particular interest given the discrepancy regarding its value from measurements with different approaches. Here, we explore the feasibility of the Vera C. Rubin Observatory Legacy Survey of Space and Time (LSST) of detecting strongly lensed SNe in the field of five galaxy clusters (Abell 1689 and Hubble Frontier Fields clusters) that have well-studied lensing models. Considering the 88 systems composed of 268 individual multiple images in the five cluster fields, we find that the LSST will be sensitive to SNe Ia (SNe IIP) exploding in 41 (23) galaxy images. The range of redshift of these galaxies is between 1.01<z<3.05. During its 10 years of operation, LSST is expected to detect 0.2±0.1 SN Ia and 0.9±0.3 core collapse SNe. However, as LSST will observe many more massive galaxy clusters, it is likely that the expectations are higher. We stress the importance of having an additional observing program for photometric and spectroscopic follow-up of the strongly lensed SNe detected by LSST.

scholarly journals Metallicity of the high-redshift Universe traced by radio galaxies

2009 ◽  
Vol 5 (S265) ◽  
pp. 179-180
Author(s):  
K. Matsuoka ◽  
T. Nagao ◽  
R. Maiolino ◽  
A. Marconi ◽  
Y. Taniguchi
Keyword(s):  
Star Formation ◽  
High Redshift ◽  
Radio Galaxies ◽  
Narrow Line ◽  
Line Flux ◽  
Model Calculations ◽  
Massive Galaxies ◽  
High Redshift Universe ◽  
Photoionization Model ◽  
Very High

AbstractWe investigate the metallicity of the narrow line regions (NLRs) of high-z radio galaxies (HzRGs), using new deep optical spectra of 9 HzRGs obtained with FORS2 on VLT and data from the literature. To estimate the metallicity of NLRs we focus on the Civ/Heii and Ciii]/Civ flux ratios. Based on comparison between the observed emission-line flux ratios and the prediction of our photoionization model calculations, we find no significant metallicity evolution in NLRs of HzRGs, up to z ~ 4. We discuss the possibility that massive galaxies had almost completed the major epoch of the star formation in the very high-z universe (z > 5).

scholarly journals The nature of 500 micron risers I: SMA observations

2020 ◽  
Vol 496 (2) ◽  
pp. 2315-2333
Author(s):  
J Greenslade ◽  
D L Clements ◽  
G Petitpas ◽  
V Asboth ◽  
A Conley ◽  
...  
Keyword(s):  
Star Formation ◽  
High Redshift ◽  
Multiple Sources ◽  
Star Forming ◽  
Strong Lensing

ABSTRACT We present SMA observations at resolutions from 0.35 to 3 arcsec of a sample of 34 candidate high redshift dusty star forming galaxies (DSFGs). These sources were selected from the HerMES Herschel survey catalogues to have SEDs rising from 250 to 350 to 500 μm, a population termed 500-risers. We detect counterparts to 24 of these sources, with four having two counterparts. We conclude that the remaining ten sources that lack detected counterparts are likely to have three or more associated sources which blend together to produce the observed Herschel source. We examine the role of lensing, which is predicted to dominate the brightest (F500 &gt; 60 mJy) half of our sample. We find that while lensing plays a role, at least 35 per cent of the bright sources are likely to be multiple sources rather than the result of lensing. At fainter fluxes we find a blending rate comparable to, or greater than, the predicted 40 per cent. We determine far-IR luminosities and star formation rates for the non-multiple sources in our sample and conclude that, in the absence of strong lensing, our 500-risers are very luminous systems with LFIR &gt; 1013 L⊙ and star formation rates &gt;1000 M⊙ yr−1.

scholarly journals The discovery of the most UV–Ly α luminous star-forming galaxy: a young, dust- and metal-poor starburst with QSO-like luminosities

2020 ◽  
Vol 499 (1) ◽  
pp. L105-L110
Author(s):  
R Marques-Chaves ◽  
J Álvarez-Márquez ◽  
L Colina ◽  
I Pérez-Fournon ◽  
D Schaerer ◽  
...  
Keyword(s):  
Star Formation ◽  
Gravitational Lensing ◽  
Active Galactic Nucleus ◽  
Star Formation Rate ◽  
High Redshift ◽  
Formation Rate ◽  
Star Forming ◽  
Evolutionary Scheme ◽  
Intense Burst

ABSTRACT We report the discovery of BOSS-EUVLG1 at z = 2.469, by far the most luminous, almost un-obscured star-forming galaxy known at any redshift. First classified as a QSO within the Baryon Oscillation Spectroscopic Survey, follow-up observations with the Gran Telescopio Canarias reveal that its large luminosity, MUV ≃ −24.40 and log(LLyα/erg s–1) ≃ 44.0, is due to an intense burst of star formation, and not to an active galactic nucleus or gravitational lensing. BOSS-EUVLG1 is a compact (reff ≃ 1.2 kpc), young (4–5 Myr) starburst with a stellar mass log(M*/M⊙) = 10.0 ± 0.1 and a prodigious star formation rate of ≃1000 M⊙ yr−1. However, it is metal- and dust-poor [12 + log(O/H) = 8.13 ± 0.19, E(B – V) ≃ 0.07, log(LIR/LUV) &lt; −1.2], indicating that we are witnessing the very early phase of an intense starburst that has had no time to enrich the ISM. BOSS-EUVLG1 might represent a short-lived (&lt;100 Myr), yet important phase of star-forming galaxies at high redshift that has been missed in previous surveys. Within a galaxy evolutionary scheme, BOSS-EUVLG1 could likely represent the very initial phases in the evolution of massive quiescent galaxies, even before the dusty star-forming phase.

scholarly journals An ALMA survey of the SCUBA-2 cosmology legacy survey UKIDSS/UDS field: Dust attenuation in high-redshift Lyman-break galaxies

2020 ◽  
Vol 492 (4) ◽  
pp. 4927-4944 ◽  
Author(s):  
M P Koprowski ◽  
K E K Coppin ◽  
J E Geach ◽  
U Dudzevičiūtė ◽  
Ian Smail ◽  
...  
Keyword(s):  
Star Formation ◽  
High Redshift ◽  
Infrared Excess ◽  
Massive Galaxies ◽  
Lyman Break Galaxies ◽  
Deep Survey ◽  
Dust Component ◽  
Stellar Masses ◽  
Dust Attenuation

ABSTRACT We analyse 870 $\mu$m Atacama Large Millimetre Array (ALMA) dust continuum detections of 41 canonically selected $z$ ≃ 3 Lyman-break galaxies (LBGs), as well as 209 ALMA-undetected LBGs, in follow-up of SCUBA-2 mapping of the UKIDSS Ultra Deep Survey (UDS) field. We find that our ALMA-bright LBGs lie significantly off the local IRX-beta relation and have relatively bluer rest-frame UV slopes (as parametrized by β), given their high values of the ‘infrared excess’ (IRX ≡ LIR/LUV), relative to the average ‘local’ IRX-β relation. We attribute this finding in part to the young ages of the underlying stellar populations but we find that the main reason behind the unusually blue UV slopes are the relatively shallow slopes of the corresponding dust attenuation curves. We show that, when stellar masses, M*, are being established via SED fitting, it is absolutely crucial to allow the attenuation curves to vary (rather than fixing it on Calzetti-like law), where we find that the inappropriate curves may underestimate the resulting stellar masses by a factor of ≃2–3× on average. In addition, we find these LBGs to have relatively high specific star-formation rates (sSFRs), dominated by the dust component, as quantified via the fraction of obscured star formation $(f_{\rm obs}\equiv {\rm SFR_{\rm IR}/{\rm SFR}_{\rm UV+IR}})$. We conclude that the ALMA-bright LBGs are, by selection, massive galaxies undergoing a burst of a star formation (large sSFRs, driven, for example, by secular or merger processes), with a likely geometrical disconnection of the dust and stars, responsible for producing shallow dust attenuation curves.

scholarly journals ALMA Deep Field in the SSA22 proto-cluster at z = 3

2019 ◽  
Vol 15 (S352) ◽  
pp. 157-161
Author(s):  
Hideki Umehata
Keyword(s):  
Star Formation ◽  
High Redshift ◽  
Three Dimensional ◽  
Filamentary Structure ◽  
Massive Black Holes ◽  
X Ray ◽  
Star Formation Activity ◽  
Suitable Target ◽  
Good Laboratory

AbstractGalaxies and nuclei in dense environment at high redshift provide a good laboratory to investigate accelerated, most extreme evolution of galaxies. The SSA22 proto-cluster at z = 3.1 is known to have a three-dimensional 50 (comoving) Mpc-scale filamentary structure, traced by Lyα emitters, which makes the field a suitable target in this regard. To identify dust-obscured star-formation, a contiguous 20 arcmin2 region at the node of the cosmic structure was observed in ALMA band 6. In total 57 ALMA sources have been identified above 5σ, which makes the field one of the richest field in ALMA-identified (sub)millimeter galaxies. The follow-up spectroscopy confirmed about 20 sources as exact proto-cluster members so far. Together with high X-ray AGN fraction, our results suggest that the vigorous star formation activity and the growth of super massive black holes occurred simultaneously in the densest regions at z ∼ 3.

scholarly journals On the dust temperatures of high-redshift galaxies

2019 ◽  
Vol 489 (1) ◽  
pp. 1397-1422 ◽  
Author(s):  
Lichen Liang ◽  
Robert Feldmann ◽  
Dušan Kereš ◽  
Nick Z Scoville ◽  
Christopher C Hayward ◽  
...  
Keyword(s):  
Star Formation ◽  
Interstellar Dust ◽  
Star Formation Rate ◽  
High Redshift ◽  
Formation Rate ◽  
Broad Band ◽  
Two Phase ◽  
High Redshift Galaxies ◽  
Dust Temperature ◽  
Redshift Galaxies

Abstract Dust temperature is an important property of the interstellar medium (ISM) of galaxies. It is required when converting (sub)millimetre broad-band flux to total infrared luminosity (LIR), and hence star formation rate, in high-redshift galaxies. However, different definitions of dust temperatures have been used in the literature, leading to different physical interpretations of how ISM conditions change with, e.g. redshift and star formation rate. In this paper, we analyse the dust temperatures of massive ($M_{\rm star} \gt 10^{10}\, \mathrm{M}_{\odot }$) $z$ = 2–6 galaxies with the help of high-resolution cosmological simulations from the Feedback in Realistic Environments (fire) project. At $z$ ∼ 2, our simulations successfully predict dust temperatures in good agreement with observations. We find that dust temperatures based on the peak emission wavelength increase with redshift, in line with the higher star formation activity at higher redshift, and are strongly correlated with the specific star formation rate. In contrast, the mass-weighted dust temperature, which is required to accurately estimate the total dust mass, does not strongly evolve with redshift over $z$ = 2–6 at fixed IR luminosity but is tightly correlated with LIR at fixed $z$. We also analyse an ‘equivalent’ dust temperature for converting (sub)millimetre flux density to total IR luminosity, and provide a fitting formula as a function of redshift and dust-to-metal ratio. We find that galaxies of higher equivalent (or higher peak) dust temperature (‘warmer dust’) do not necessarily have higher mass-weighted temperatures. A ‘two-phase’ picture for interstellar dust can explain the different scaling relations of the various dust temperatures.

scholarly journals Spatial distribution of the gamma-ray bursts at very high redshift

2017 ◽  
Vol 12 (S333) ◽  
pp. 203-206
Author(s):  
Attila Mészáros
Keyword(s):  
Spatial Distribution ◽  
Star Formation ◽  
Gamma Ray ◽  
Star Formation Rate ◽  
High Redshift ◽  
Formation Rate ◽  
Gamma Ray Bursts ◽  
Cosmological Principle ◽  
Statistical Studies ◽  
Very High

AbstractThe author - with his collaborators - already in years 1995-96 have shown - purely from the analyses of the observations - that the gamma-ray bursts (GRBs) can be till redshift 20. Since that time several other statistical studies of the spatial distribution of GRBs were provided. Remarkable conclusions concerning the star-formation rate and the validity of the cosmological principle were obtained about the regions of the cosmic dawn. In this contribution these efforts are surveyed.

Neurological manifestation in severe hypothyroidism in pregnancy

2020 ◽  
Vol 13 (12) ◽  
pp. e238069
Author(s):  
Aparna Sharma ◽  
Nilofar Noor ◽  
Vatsla Dadhwal
Keyword(s):  
Peripheral Neuropathy ◽  
Facial Palsy ◽  
Caesarean Delivery ◽  
Thyroid Stimulating Hormone ◽  
Neurological Manifestations ◽  
Second Trimester ◽  
Pituitary Hyperplasia ◽  
Very High ◽  
In Pregnancy

Neurological manifestations of hypothyroidism include peripheral neuropathy and pituitary hyperplasia. However, these associations are rarely encountered during pregnancy. We report a case of a known hypothyroid with very high thyroid stimulating hormone (TSH) values (512 μIU/mL) in the second trimester. At 24 weeks she developed facial palsy and pituitary hyperplasia which responded to a combination of steroids and thyroxine. She had caesarean delivery at 35 weeks and 3 days gestation in view of pre-eclampsia with severe features and was discharged on oral antihypertensives and thyroxine. On follow-up at 5 months, TSH normalised and pituitary hyperplasia showed a greater than 50% reduction in size. To our knowledge, this is the first reported case of facial palsy and pituitary hyperplasia associated with hypothyroidism during pregnancy.

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