The Institute of Astrophysics of Andalusia [Instituto de Astrofísica de Andalucía] CSIC (ES) via Manu Garcia, a friend from IAC-Institute of Astrophysics of the Canaries[Instituto de Astrofísica de Canarias](ES): “An isolated dwarf galaxy unexpectedly affected by its environment”

The Institute of Astrophysics of Andalusia [Instituto de Astrofísica de Andalucía] CSIC (ES)

via


Manu Garcia, a friend from IAC-Institute of Astrophysics of the Canaries[Instituto de Astrofísica de Canarias](ES).

The universe around us.
Astronomy, everything you wanted to know about our local universe and never dared to ask.

6.13.22

Silbia López de Lacalle – sll@iaa.es

1
The WLM (ESO) galaxy.

Dwarf galaxies are affected by all the evolutionary processes that normally occur in galaxies of any mass. Being fainter and less massive galaxies, they are especially susceptible to environmental mechanisms caused by a nearby giant galaxy, such as gravitational tides or drag pressure due to the surrounding gaseous medium. These effects are considered the main differences between the ‘satellite’ and ‘field’ (or ‘isolated’) dwarf galaxy populations.

WLM was discovered in 1909 by Max Wolf, and later confirmed by Knut Lundmark and Philibert Melotte (hence the name, WLM). It lies about three million light-years from both the Milky Way and Messier 31 [Andromeda], and is believed to be an archetypal isolated dwarf galaxy that formed in complete isolation without external disturbances. Previous studies suggest that the amount of dark matter in this galaxy is up to ninety times higher than the amount of ordinary matter (composed of stars and gas).

2
Direction of movement of the galaxy.

WLM was recently observed by the recently built MeerKAT radio telescope, a precursor to the Square Kilometer Array (SKA) in Africa.

From deep-sea data, the science team identified four clouds of neutral hydrogen (HI) extending in the northwest direction of WLM, in the opposite direction of its motion in the sky based on data from the Gaia satellite.

Roger Ianjamasimanana, a researcher at the Institute of Astrophysics of Andalusia (IAA-CSIC) who participates in the work, explains: “The four clouds represent 10% of the total mass of neutral hydrogen in the galaxy. We have also found that there is a spatial gap between the WLM gas and the stars.”

The study of these four clouds has led to the conclusion that the WLM gas is subjected to a strong wind from the surrounding gaseous medium that crosses the galaxy and that it is expelling the gas out of the galaxy. Lead author Yanbin Yang (Paris Observatory and CNRS) clarifies why this is so surprising: “The intergalactic medium in which WLM resides is assumed to be nearly empty. Until now we had assumed that there was nothing that could have this effect in a galaxy.”

Science paper:
Astronomy & Astrophysics

The team ran computer simulations to study the effect in more detail. “Also in our simulations we find that the observations can only be explained if the intergalactic medium were much denser than expected. It seems that we have found a very large and unexpected reservoir of matter in the filamentary structure of the universe, “says Yang. Another possible explanation would be that the mass of WLM is much lower and that it does not have the percentage of dark matter attributed to it. But this would be revolutionary, since the mass of galaxies is believed to be dominated by this invisible component that only interacts gravitationally. Regardless of the explanation, this study revolutionizes the understanding of dwarf galaxies, which can no longer be considered totally isolated.

See the full article here .

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Welcome to the Instituto de Astrofísica de Andalucía (IAA). The IAA is an institute of The Spanish National Research Council[Consejo Superior de Investigaciones Científicas (CSIC) (ES). The activities of the IAA (CSIC) are related to research in the field of Astrophysics and the development of instruments for telescopes and space vehicles. These webpages are intended to present our activities as well as useful information both for other professional institutions devoted to astrophysics research as well as for those interested in learning something more about the IAA and astrophysics in general.

From the front page on, an explanation is provided of the structure and organization of the IAA, followed by general information concerning our technological and scientific research in addition to all the activities we consider of general interest.

The pages of each department provide basic information: the staff, research lines, projects under way and research results. The navigator will also find more specific and varied information on each of the individual pages of the IAA staff.

Introduction
The IAA has as its general scientific objective to help increase the bulk of knowledge about our universe, from the closest at hand, our solar system, to an overall scale of the entire universe, improving descriptions and analysing the physical processes that take place there. The nature of this aim demands a multi-disciplinary approach, requiring a combination of theory, observation and technology in different areas of physics and engineering. Although the IAA is a centre for pursuing basic science, we are aware of the role that astrophysics plays as a user and producer of new technologies.

To achieve our overarching objective, different scientific programmes are being undertaken with specific aims and timetables, encompassing four large areas of astrophysics: the solar system; star formation, structure and evolution; galaxy structure and evolution; and cosmology. Basic science has been and continues to be the motor for training scientific and technical staff, as well as for stimulating the development of other disciplines. The history of the IAA clearly depicts the observational function of the centre.

The telescopes installed in the Observatorio de Sierra Nevada (OSN), reflect a scientific policy with the clear objective of ensuring continued access to observational means to undertake far-reaching scientific projects.


This fact adds singularity to the centre and at the same time offers the challenge and incentive for research at the IAA. The design and construction of instruments for the OSN, as well as others to be carried in special space vehicles, not only serve as support for basic research by the different teams of the IAA, but also represent activity of prime importance for the appropriate combination of research and development.

The Institute of Astrophysics of Andalusia [Instituto de Astrofísica de Andalucía, IAA-CSIC] is a research institute funded by the High Council of Scientific Research of the Spanish government Consejo Superior de Investigaciones Científicas (CSIC), and is located in Granada, Andalusia, Spain. IAA activities are related to research in the field of astrophysics, and instrument development both for ground-based telescopes and for space missions. Scientific research at the Institute covers the solar system, star formation, stellar structure and evolution, galaxy formation and evolution and cosmology. The IAA was created as a CSIC research institute in July 1975. Presently, the IAA operates the Sierra Nevada Observatory, and (jointly with the also the The MPG Institute for Astronomy [MPG Institut für Astronomie](DE)) the Calar Alto Observatory.

Calar Alto Astronomical Observatory 3.5 meter Telescope, located in Almería province in Spain on Calar Alto, a 2,168-meter-high (7,113 ft) mountain in Sierra de Los Filabres(ES)
The Instituto de Astrofísica de Andalucía is divided in the following departments, each with an (incomplete) outline of research avenues and groups:

Department of Extragalactic Astronomy
Violent Stellar Formation Group
AMIGA Group (Analysis of the interstellar Medium of Isolated Galaxies)
Department of Stellar Physics
Department of Radio Astronomy and Galactic Structure
Stellar Systems Group
Department of Solar System

The technological needs of IAA’s research groups are fulfilled by the Instrumental and Technological Developments Unit