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Title: Beacons In the Dark: Using Novae and Supernovae to Detect Dwarf Galaxies in the Local Universe
Author: Charlie Conroy, James S. Bullock

We propose that luminous transients, including novae and supernovae, can be used to detect the faintest galaxies in the universe. Beyond a few Mpc, dwarf galaxies with stellar masses <106 solar masses will likely be too faint and/or too low in surface brightness to be directly detected in upcoming large area ground-based photometric surveys. However, single epoch LSST photometry will be able to detect novae to distances of ~30 Mpc and SNe to Gpc-scale distances. Depending on the form of the stellar mass-halo mass relation and the underlying star formation histories of low mass dwarfs, the expected nova rates will be a few to ~100 yr-1 and the expected SN rates (including both type Ia and core-collapse) will be ~102-104 within the observable (4 pi sr) volume. The transient rate associated with intrahalo stars will be comparably large, but these transients will be located close to bright galaxies, in contrast to the dwarfs, which should trace the underlying large scale structure of the cosmic web. Aggressive follow-up of hostless transients has the potential to uncover the predicted enormous population of low mass field dwarf galaxies.

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NASA's Hubble Finds Dwarf Galaxies Formed More Than Their Fair Share of Universe's Stars

They may be little, but they pack a big star-forming punch. New observations from NASA's Hubble Space Telescope show small galaxies, also known as dwarf galaxies, are responsible for forming a large proportion of the universe's stars.
Studying this early epoch of the universe's history is critical to fully understanding how these stars formed and how galaxies grew and evolved 3.5 to 6 billion years after the beginning of the universe. The result supports a decade-long investigation into whether there is a link between a galaxy's mass and its star-forming activity, and helps paint a consistent picture of events in the early universe.

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Title: Dwarf Galaxies and the Cosmic Web
Authors: Alejandro Benitez-Llambay, Julio F. Navarro, Mario G. Abadi, Stefan Gottloeber, Gustavo Yepes, Yehuda Hoffman, Matthias Steinmetz

We use a cosmological simulation of the formation of the Local Group of Galaxies to identify a mechanism that enables the removal of baryons from low-mass halos without appealing to feedback or reionisation. As the Local Group forms, matter bound to it develops a network of filaments and pancakes. This moving web of gas and dark matter drifts and sweeps a large volume, overtaking many halos in the process. The dark matter content of these halos is unaffected but their gas can be efficiently removed by ram-pressure. The loss of gas is especially pronounced in low-mass halos due to their lower binding energy and has a dramatic effect on the star formation history of affected systems. This "cosmic web stripping" may help to explain the scarcity of dwarf galaxies compared with the numerous low-mass halos expected in \Lambda CDM and the large diversity of star formation histories and morphologies characteristic of faint galaxies. Although our results are based on a single high-resolution simulation, it is likely that the hydrodynamical interaction of dwarf galaxies with the cosmic web is a crucial ingredient so far missing from galaxy formation models.

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Hubble Unmasks Ghost Galaxies

Astronomers have puzzled over why some puny, extremely faint dwarf galaxies spotted in our Milky Way galaxy's back yard contain so few stars. These ghost-like galaxies are thought to be some of the tiniest, oldest, and most pristine galaxies in the universe. They have been discovered over the past decade by astronomers using automated computer techniques to search through the images of the Sloan Sky Survey. But astronomers needed NASA's Hubble Space Telescope to help solve the mystery of these star-starved galaxies.
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Dwarf Galaxies in the Local Supercluster
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Title: A List of Dwarf Galaxies in the Local Supercluster
Authors: D. I. Makarov, R. I. Uklein

We report a list of groups consisting of dwarf galaxies only. The sample contains 126 objects, mainly combined in pairs. The most populated group contains six dwarf galaxies. The majority of systems considered reside in the low-density regions and evolve unaffected by massive galaxies. The characteristic sizes and velocity dispersions of groups are 30 kpc and 11 km/s, respectively. They resemble the associations of dwarf galaxies, but are more compact. On the whole, groups and associations form a continuous sequence. Alike the associations, our groups possess high mass-to-luminosity ratios, what is indicative of a large amount of dark matter present in these systems.

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CANDELS

Using its near-infrared vision to peer 9 billion years back in time, NASA's Hubble Space Telescope has uncovered an extraordinary population of tiny, young galaxies that are brimming with star formation. The galaxies are typically a hundred times less massive than the Milky Way galaxy, yet they churn out stars at such a furious pace that their stellar content would double in just 10 million years. By comparison, the Milky Way would take a thousand times longer to double its population. The observations were part of the Cosmic Assembly Near-infrared Deep Extragalactic Legacy Survey (CANDELS), an ambitious three-year survey to analyse the most distant galaxies in the universe. CANDELS is the census of dwarf galaxies at such an early epoch in the universe's history. This video zooms into the Hubble GOODS South Deep (GSD) field and the Hubble Ultra Deep Survey (UDS) 



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Hubble Uncovers Tiny Galaxies Bursting with Starbirth in Early Universe

Using its infrared vision to peer nine billion years back in time, the NASA/ESA Hubble Space Telescope has uncovered an extraordinary population of tiny, young galaxies that are brimming with star formation.
The galaxies are churning out stars at such a rate that the number of stars in them would double in just ten million years. For comparison, the Milky Way has taken a thousand times longer to double its stellar population.
These newly discovered dwarf galaxies are around a hundred times smaller than the Milky Way. Their star formation rates are extremely high, even for the young Universe, when most galaxies were forming stars at higher rates than they are today. They have turned up in the Hubble images because the radiation from young, hot stars has caused the oxygen in the gas surrounding them to light up like a fluorescent sign.
Astronomers believe this rapid starbirth represents an important phase in the formation of dwarf galaxies, the most common galaxy type in the cosmos.

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Puzzling dwarf galaxies finally make sense
Supercomputer model factored in a phenomenon known as stellar wind

It has long been a mystery why small galaxies don't have as many stars and matter in their centers as predicted. Now scientists have found the answer with a new simulation of galaxy and star formation.
All galaxies are thought to form inside large cradles of invisible stuff called dark matter. Scientists can't measure dark matter directly, but they suspect it's there because of its telltale gravitational tug on regular matter. And miniature galaxies called dwarf galaxies seem to have even higher proportions of dark matter than regular galaxies.

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Australian astronomers have discovered that the universe is peppered with tiny blue dwarf galaxies known as 'blue fuzzies'.
These tiny galaxies are made up mostly of young hot stars that shine brightly, dominating the light from the galaxies they are in.
According to a report in ABC News, Dr Sarah Brough of the Anglo-Australian Observatory made the discovery while examining data from a study called the Galaxy and Mass Assembly survey (GAMA).

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