‘Peekabo’ dwarf galaxy is extremely metal-poor, study finds

Utilizing the Southern African Massive Telescope (SALT) and the Hubble Area Telescope (HST), a global staff of astronomers have noticed the dwarf galaxy HIPASS J1131–31, dubbed the “Peekabo Galaxy.” The observational marketing campaign has discovered that Peekabo is without doubt one of the most extraordinarily metal-poor galaxies recognized so far. The invention was reported in a paper revealed in Month-to-month Notices of the Royal Astronomical Society.

Detected in 2001 because it emerged from behind a shiny fast-moving star often called TYC 7215-199-1, Peekabo is a close-by dwarf irregular galaxy situated some 21.8 million light years away. Earlier observations of this galaxy, tough to carry out because of the glare of TYC 7215-199-1, have steered that it’s a comparatively younger system showcasing a low chemical enrichment stage.

Lately, a gaggle of astronomers led by Igor D. Karachentsev of the Particular Astrophysical Observatory (SAO) in Russia has investigated Peekabo with SALT and HST, with a view to acquire extra details about the properties and chemical composition of this galaxy. The research was accomplished by archival knowledge from the Australia Telescope Compact Array (ATCA).

“The dwarf galaxy HIPASS J1131–31 was noticed with the Hubble Area Telescope (HST) Superior Digital camera for Surveys (ACS) on July 14, 2020, for 760 seconds in every of the 𝐼- and 𝑉-bands as part of the ‘Each Identified Close by Galaxy’ survey. … We carried out long-slit optical spectroscopic observations of the Peekaboo galaxy utilizing the Robert Stobie Spectrograph (RSS) put in on the Southern African Massive Telescope (SALT) on February 22, 2022,” the researchers wrote within the paper.

The optical spectral observations discovered that Peekaboo is a gas-rich dwarf galaxy with a impartial atomic hydrogen (H I) mass of log(MHI/solar mass) at a stage of seven.08. It turned out that Peekaboo is without doubt one of the most extraordinarily metal-poor galaxies recognized with the gas-phase oxygen abundance [12+log(O/H)] of roughly 6.99 dex.

In accordance with the research, Peekaboo has an absolute magnitude of −11.27 magazine, a half-light radius of about 391 gentle years and its central floor brightness is at a stage of twenty-two.0 magazine/arcsec². The gap to the galaxy was calculated to be roughly 22.2 million gentle years.

The astronomers assume that Peekaboo is a possible member of the scattered affiliation of late-type dwarf galaxies across the galaxy NGC 3621. This group, with dimensions of between 3.2 and 5.9 million gentle years, is situated in a really low density area between the Native Sheet and Dorado–Leo Spur–Antlia mini-wall.

The research additionally discovered that Peekaboo hosts a comparatively low quantity of purple big department (RGB) stars. The discovering means that the star formation course of on this galaxy started in the previous few billion years, so the system is devoid of historic stellar populations.

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