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Three new ultra-weak dwarf galaxies have been discovered

DSS image centered on NGC 253. It shows the area explored by PISCeS extending from the center up to 100 kpc. The solid blue circle represents the location of the dwarf previously discovered on PIS CeS. Credits: Mutlu-Pakdil et al. , 2021.

Using the Hubble Space Telescope (HST), astronomers have detected three new ultra-weak dwarf galaxies associated with the nearby spiral galaxy NGC253. The findings are reported in a paper published on arXiv.org on August 20th.

So-called super faint dwarf Galaxy (UFD) has the lowest luminosity and the brightest Dark matter The dominant and chemically least evolved galaxies are known. Therefore, they are early recognized by astronomers as the best candidate fossils from space.

The Centaurus and Sculptor Panorama Imaging Survey (PISCeS) project is one of the astronomical surveys aimed at discovering new faint satellite galaxies, including UFDs. As part of PISCeS, a team of astronomers led by Burçin Mutlu-Pakdil at the University of Chicago searched for a satellite dwarf system and observed fields around NGC253 at HST.At a distance of about 11.4 million Light year, NGC 253 is the major galaxy of the nearby Chokokushi group.

The team visually inspected everything imageSearching for spatially compact overdensity of stars around NGC 253, we found three new UFDs in addition to the two known UFDs identified in 2014 and 2016.

“In this work, we report the discovery of three super-faint dwarfs. Hygiene A panoramic image campaign to find the faint substructure of the NGC253 galaxy in a visual search of Magellan / Megacam images taken as part of PISCeS

The newly discovered UFDs have been named Scl-MM-dw3, Scl-MM-dw4, and Scl-MMdw5. Astronomers consider them to be primitive fossils from the era of reionization, as they are uniformly old (estimated age is about 12 billion years) and almost all stars are formed in the early universe.

Scl-MM-dw3 is the smallest UFD in the newly detected trio, as the elliptical semi-light radius along the semi-major axis is estimated to be approximately 362 light-years. The galaxy is about 11.34 million light-years away from Earth and about 264,000 light-years away from NGC 253. The mass of the star was calculated to be at the level of 110,000 solar masses.

It turns out that Scl-MM-dw4 is as large as Scl-MM-dw3, but almost 70% larger, with a half-light radius measured at 613 light-years. The UFD is about 13.37 million light-years away, and the distance to NGC253 is estimated to be about 280,300 light-years.

The Scl-MM-dw5 is the largest and heaviest dwarf of the three new UFDs, with a semi-optical radius of about 1,167 and a mass of about 140,000 solar masses. The galaxy is about 12.71 million light-years away from Earth and about 313,000 light-years away from NGC253.

Astronomers emphasized that the newly discovered dwarfs have a luminosity of -7.5 to -7.24 mag. This places these dwarfs in the darkest galaxies identified outside our local group.


Astronomers Discover Three New Faint Dwarf Galaxy


For more information:
Burçin Mutlu-Pakdiletal, NGC 253 Hubble Space Telescope Observations of Dwarf Galaxy: Discovery of Three Ultra-Weak Dwarf Galaxy, arXiv: 2108.09312 [astro-ph.GA] arxiv.org/abs/2108.09312

© 2021 Science X Network

Quote: Three new ultra-weak dwarf galaxies discovered (31 August 2021) from https: //phys.org/news/2021-08-ultra-faint-dwarf-galaxies.html 31 August 2021 Obtained on the day

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Three new ultra-weak dwarf galaxies have been discovered

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