Spiral morphology in an intensely star-forming disk galaxy more than 12 billion years ago

Spiral galaxies have distinct internal structures including a stellar bulge, disk and spiral arms. It is unknown when in cosmic history these structures formed. We analyze observations of BRI 1335–0417, an intensely star-forming galaxy in the distant Universe, at redshift 4.41. The [C ii] gas kinematics show a steep velocity rise near the galaxy center and have a two-armed spiral morphology, which extends from about 2 to 5 kiloparsecs in radius. We interpret these features as due to a central compact structure, such as a bulge; a rotating gas disk; and either spiral arms or tidal tails. These features had formed within 1.4 billion years after the Big Bang, long before the peak of cosmic star formation.

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Fast molecular outflow from a dusty star-forming galaxy in the early Universe

Science ◽

10.1126/science.aap8900 ◽

2018 ◽

Vol 361 (6406) ◽

pp. 1016-1019 ◽

Cited By ~ 37

Author(s):

J. S. Spilker ◽

M. Aravena ◽

M. Béthermin ◽

S. C. Chapman ◽

C.-C. Chen ◽

...

Keyword(s):

Star Formation ◽

High Redshift ◽

Large Fraction ◽

Formation Rate ◽

Free Fall ◽

Big Bang ◽

Star Forming ◽

Molecular Outflow ◽

The Galaxy ◽

The Big Bang

Galaxies grow inefficiently, with only a small percentage of the available gas converted into stars each free-fall time. Feedback processes, such as outflowing winds driven by radiation pressure, supernovae, or supermassive black hole accretion, can act to halt star formation if they heat or expel the gas supply. We report a molecular outflow launched from a dust-rich star-forming galaxy at redshift 5.3, 1 billion years after the Big Bang. The outflow reaches velocities up to 800 kilometers per second relative to the galaxy, is resolved into multiple clumps, and carries mass at a rate within a factor of 2 of the star formation rate. Our results show that molecular outflows can remove a large fraction of the gas available for star formation from galaxies at high redshift.

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Li isotopes in metal-poor halo dwarfs: a more and more complicated story

Proceedings of the International Astronomical Union ◽

10.1017/s1743921310004138 ◽

2009 ◽

Vol 5 (S268) ◽

pp. 201-210

Author(s):

Monique Spite ◽

François Spite

Keyword(s):

Cosmic Rays ◽

Big Bang ◽

The Other ◽

Big Bang Nucleosynthesis ◽

Lithium Abundance ◽

The Galaxy ◽

Li Isotope ◽

Low Metallicity ◽

The Big Bang ◽

Early Galaxy

AbstractThe nuclei of the lithium isotopes are fragile, easily destroyed, so that, at variance with most of the other elements, they cannot be formed in stars through steady hydrostatic nucleosynthesis.The 7Li isotope is synthesized during primordial nucleosynthesis in the first minutes after the Big Bang and later by cosmic rays, by novae and in pulsations of AGB stars (possibly also by the ν process). 6Li is mainly formed by cosmic rays. The oldest (most metal-deficient) warm galactic stars should retain the signature of these processes if, (as it had been often expected) lithium is not depleted in these stars. The existence of a “plateau” of the abundance of 7Li (and of its slope) in the warm metal-poor stars is discussed. At very low metallicity ([Fe/H] < −2.7dex) the star to star scatter increases significantly towards low Li abundances. The highest value of the lithium abundance in the early stellar matter of the Galaxy (logϵ(Li) = A(7Li) = 2.2 dex) is much lower than the the value (logϵ(Li) = 2.72) predicted by the standard Big Bang nucleosynthesis, according to the specifications found by the satellite WMAP. After gathering a homogeneous stellar sample, and analysing its behaviour, possible explanations of the disagreement between Big Bang and stellar abundances are discussed (including early astration and diffusion). On the other hand, possibilities of lower productions of 7Li in the standard and/or non-standard Big Bang nucleosyntheses are briefly evoked.A surprisingly high value (A(6Li)=0.8 dex) of the abundance of the 6Li isotope has been found in a few warm metal-poor stars. Such a high abundance of 6Li independent of the mean metallicity in the early Galaxy cannot be easily explained. But are we really observing 6Li?

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Deuterium in the Galaxy

Publications of the Astronomical Society of Australia ◽

10.1017/s1323358000014910 ◽

1977 ◽

Vol 3 (2) ◽

pp. 100-101 ◽

Cited By ~ 1

Author(s):

R. D. Brown

Keyword(s):

Great Majority ◽

Big Bang ◽

Baryon Density ◽

The Galaxy ◽

Mass Fractions ◽

Expansion Of The Universe ◽

Sensitive Function ◽

The Big Bang ◽

Deuterium Production ◽

The Universe

There have been a number of attempts made in the last decade or two to observe deuterium in parts of the universe other than here in Earth. It is of interest merely to detect deuterium elsewhere just as it is to detect the occurrence of any nuclide. However in the case of deuterium there is a special interest because in big-bang cosmologies the great majority of deuterium in the universe is considered to have been formed in the initial fireball (Wagoner, 1973). Any observation of the present abundance of deuterium thus might give information about the very early stages of the creation of the universe. Detailed studies of nucleosynthesis during the early expansion of hot big-bang universes have however indicated a particular feature of deuterium production. (Fig. 1) The mass fraction produced X(D) is a very sensitive function of the size of the universe, as measured say by the present baryon density ϱb. Other nuclides that are mainly produced in the early expansion, such as 4He, have mass fractions less dependent on ϱb. Thus if we adopt the big-bang model for our universe we can determine ϱb from observations of X(D). Apart from any intrinsic interest in the present density of the’universe, there is considerable interest in whether the value is great enough for the present expansion to halt and go over to a collapse — or so small that the expansion of the universe will go on forever.

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Dark Matter in the Universe

Highlights of Astronomy ◽

10.1017/s1539299600006134 ◽

1986 ◽

Vol 7 ◽

pp. 27-38 ◽

Cited By ~ 5

Author(s):

Vera C. Rubin

Keyword(s):

Dark Matter ◽

Deceleration Parameter ◽

Big Bang ◽

Theoretical Cosmology ◽

Observational Cosmology ◽

The Past ◽

The Galaxy ◽

Expansion Of The Universe ◽

The Big Bang ◽

The Universe

Thirty years ago, observational cosmology consisted of the search for two numbers: Ho, the rate of expansion of the universe at the position of the Galaxy; and qo, the deceleration parameter. Twenty years ago, the discovery of the relic radiation from the Big Bang produced another number, 3oK. But it is the past decade which has seen the enormous development in both observational and theoretical cosmology. The universe is known to be immeasurably richer and more varied than we had thought. There is growing acceptance of a universe in which most of the matter is not luminous. Nature has played a trick on astronomers, for we thought we were studying the universe. We now know that we were studying only the small fraction of it that is luminous. I suspect that this talk this evening is the first IAU Discourse devoted to something that astronomers cannot see at any wavelength: Dark Matter in the Universe.

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Dissecting star formation in the “Atoms-for-Peace” galaxy

Astronomy and Astrophysics ◽

10.1051/0004-6361/201832705 ◽

2018 ◽

Vol 614 ◽

pp. A130 ◽

Cited By ~ 2

Author(s):

K. George ◽

P Joseph ◽

P. Côté ◽

S. K. Ghosh ◽

J. B. Hutchings ◽

...

Keyword(s):

Star Formation ◽

Dwarf Galaxies ◽

Initial Conditions ◽

Dwarf Galaxy ◽

Main Body ◽

Star Forming ◽

Uv Imaging ◽

Star Forming Regions ◽

The Galaxy ◽

Tidal Tails

Context. The tidal tails of post-merger galaxies exhibit ongoing star formation far from their disks. The study of such systems can be useful for our understanding of gas condensation in diverse environments. Aims. The ongoing star formation in the tidal tails of post-merger galaxies can be directly studied from ultraviolet (UV) imaging observations. Methods. The post merger galaxy NGC7252 (“Atoms-for-Peace” galaxy) is observed with the Astrosat UV imaging telescope (UVIT) in broadband NUV and FUV filters to isolate the star-forming regions in the tidal tails and study the spatial variation in star formation rates. Results. Based on ultraviolet imaging observations, we discuss star-forming regions of ages <200 Myr in the tidal tails. We measure star formation rates in these regions and in the main body of the galaxy. The integrated star formation rate (SFR) of NGC7252 (i.e., that in the galaxy and tidal tails combined) without correcting for extinction is found to be 0.81 ± 0.01 M⊙ yr−1. We show that the integrated SFR can change by an order of magnitude if the extinction correction used in SFR derived from other proxies are taken into consideration. The star formation rates in the associated tidal dwarf galaxies (NGC7252E, SFR = 0.02 M⊙ yr−1 and NGC7252NW, SFR = 0.03 M⊙ yr−1) are typical of dwarf galaxies in the local Universe. The spatial resolution of the UV images reveals a gradient in star formation within the tidal dwarf galaxy. The star formation rates show a dependence on the distance from the centre of the galaxy. This can be due to the different initial conditions responsible for the triggering of star formation in the gas reservoir that was expelled during the recent merger in NGC7252.

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A Gaseous Group with Unusual Remote Star Formation

Publications of the Astronomical Society of Australia ◽

10.1071/as11008 ◽

2011 ◽

Vol 28 (3) ◽

pp. 271-279 ◽

Cited By ~ 2

Author(s):

N. Santiago-Figueroa ◽

M. E. Putman ◽

J. Werk ◽

G. R. Meurer ◽

E. Ryan-Weber

Keyword(s):

Star Formation ◽

Spiral Galaxy ◽

Dwarf Galaxies ◽

Dwarf Galaxy ◽

Spiral Arms ◽

Gaseous Disk ◽

Ram Pressure ◽

The Galaxy ◽

Galaxy Center ◽

Region 10

AbstractWe present VLA 21-cm observations of the spiral galaxy ESO 481-G017 to determine the nature of remote star formation traced by an Hii region found 43 kpc and ∼800 km s−1 from the galaxy center (in projection). ESO 481-G017 is found to have a 120 kpc Hi disk with a mass of 1.2 × 1010M⊙ and UV GALEX images reveal spiral arms extending into the gaseous disk. Two dwarf galaxies with Hi masses close to 108M⊙ are detected at distances of ∼200 kpc from ESO 481-G017 and a Hi cloud with a mass of 6 × 107M⊙ is found near the position and velocity of the remote Hii region. The Hii region is somewhat offset from the Hi cloud spatially and there is no link to ESO 481-G017 or the dwarf galaxies. We consider several scenarios for the origin of the cloud and Hii region and find the most likely is a dwarf galaxy that is undergoing ram pressure stripping. The Hi mass of the cloud and Hi luminosity of the Hii region (1038.1 erg s−1) are consistent with dwarf galaxy properties, and the stripping can trigger the star formation as well as push the gas away from the stars.

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What can distant galaxies teach us about massive stars?

Proceedings of the International Astronomical Union ◽

10.1017/s1743921317002927 ◽

2016 ◽

Vol 12 (S329) ◽

pp. 305-312 ◽

Cited By ~ 1

Author(s):

Elizabeth R. Stanway

Keyword(s):

Massive Stars ◽

High Redshift ◽

Stellar Populations ◽

Big Bang ◽

Limited Data ◽

Star Forming ◽

Star Models ◽

Distant Galaxies ◽

High Redshift Universe ◽

The Big Bang

AbstractObservations of star-forming galaxies in the distant Universe (z > 2) are starting to confirm the importance of massive stars in shaping galaxy emission and evolution. Inevitably, these distant stellar populations are unresolved, and the limited data available must be interpreted in the context of stellar population synthesis models. With the imminent launch of JWST and the prospect of spectral observations of galaxies within a gigayear of the Big Bang, the uncertainties in modelling of massive stars are becoming increasingly important to our interpretation of the high redshift Universe. In turn, these observations of distant stellar populations will provide ever stronger tests against which to gauge the success of, and flaws in, current massive star models.

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The beauty of resolution: The SN Ib factory NGC 2770 spatially resolved

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314009594 ◽

2014 ◽

Vol 10 (S309) ◽

pp. 169-170

Author(s):

C. C. Thöne ◽

L. Christensen ◽

J. Gorosabel ◽

A. de Ugarte Postigo

Keyword(s):

Stellar Population ◽

Late Type ◽

Spiral Arms ◽

Star Forming ◽

Spatially Resolved ◽

Star Forming Regions ◽

The Galaxy ◽

History Of ◽

First Time

AbstractThe late-type spiral NGC 2770 hosted 3 Type Ib supernovae (SNe) in or next to star-forming regions in its outer spiral arms. We study the properties of the SN sites and the galaxy at different spatial resolutions to infer propeties of the SN progenitors and the SF history of the galaxy. Several 3D techniques are used and, for the first time, we present images of metallicity, shocks and stellar population ages from OSIRIS/GTC imaging with tunable narrowband filters.

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History of the solar environment

Proceedings of the International Astronomical Union ◽

10.1017/s1743921309029706 ◽

2008 ◽

Vol 4 (S257) ◽

pp. 465-470

Author(s):

Kurt Marti ◽

Bernard Lavielle

Keyword(s):

Time Scales ◽

Decay Product ◽

Galactic Cosmic Rays ◽

Solar Neighborhood ◽

Iron Meteorites ◽

Spiral Arms ◽

Star Forming ◽

Star Forming Regions ◽

The Galaxy ◽

Flux Increase

AbstractGalactic cosmic rays (GCR) provide information on the solar neighborhood during the sun's motion in the galaxy. There is now considerable evidence for GCR acceleration by shock waves of supernova in active star-forming regions (OB associations) in the galactic spiral arms. During times of passage into star-forming regions increases in the GCR-flux are expected. Recent data from the Spitzer Space Telescope (SST) are shedding light on the structure of the Milky Way and of its star-forming-regions in spiral arms. Records of flux variations may be found in solar system detectors, and iron meteorites with GCR-exposure times of several hundred million years have long been considered to be potential detectors (Voshage, 1962). Variable concentration ratios of GCR-produced stable and radioactive nuclides, with varying half-lives and therefore integration times, were reported by Lavielleet al. (1999), indicating a recent 38% GCR-flux increase. Potential flux recorders consisting of different pairs of nuclides can measure average fluxes over different time scales (Lavielleet al., 2007; Mathew and Marti, 2008). Specific characteristics of two pairs of recorders (81Kr-Kr and129I-129Xe) are the properties of self-correction for GCR-shielding (flux variability within meteorites of varying sizes). The81Kr-Kr method (Marti, 1967) is based on Kr isotope ratios, while stable129Xe is the decay product of the radionuclide129I, which is produced by secondary neutron reactions on Te in troilites of iron meteorites. The two chronometers provide records of the average GCR flux over 1 and 100 million year time scales, respectively.

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