Commission H1 The Local Universe


The Global Dynamical Atlas of the Milky Way Mergers: Constraints from Gaia EDR3–based Orbits of Globular Clusters, Stellar Streams, and Satellite Galaxies

Figure: The Galactic maps showing phase-space measurements of n = 257 halo objects used in the study, namely 170 globular clusters (denoted by "star" markers), 41 stellar streams (denoted by "dot" markers), and 46 satellite galaxies (denoted by "square" markers). From panel (a) to (d), these objects are colored by their heliocentric distances, line-of-sight velocities, proper motion in the Galactic longitude direction, and proper motion in the Galactic latitude direction direction, respectively. In panel (d), authors show streams with their names and do not plot other objects to avoid crowding.

We congratulate our colleagues Khyati Malhan, Rodrigo A. Ibata, Sanjib Sharma, Benoit Famaey, Michele Bellazzini, Raymond G. Carlberg, Richard D'Souza, Zhen Yuan, Nicolas F. Martin, and Guillaume F. Thomas for this exciting study using the the ESA Gaia space mission data. 

Publication: Khyati Malhan et al. 2022, ApJ, 926, 107

DOI: 10.3847/1538-4357/ac4d2a

See also the presentation on the Commission H1 YouTube channel. 



IAU Commission H1 "The Local Universe" Seminar

Dear Colleagues,

We are pleased to announce that our commission launches a new online seminar series. This is primarily for IAU commission H1 members, but will be opened to everyone who have interest in the Local Universe.

In the past two years, whereas many conferences were canceled due to COVID-19, rich experiences of online meetings opened new possibilities to promote exchanging scientific achievements and ideas between members of our commission who have many common interests.

The organizing committee decided to start a seminar series that will be held via Zoom and YouTube once per month (tentatively) and will cover both hot topics and long-term work. The seminars will be recorded and listed on IAU YouTube for asynchronous viewing.

This is an announcement to the commission members to call for speakers of the seminars.
Please fill the online application form: 
or send us the following information via email to Wako Aoki (Commission H1 secretary)

Application form:

  • Name and Surname:
  • Affiliation:
  • E-mail:
  • Preferred duration of the talk: Keynote (25 min + 15 min) or Highlights (12 min + 8 min)
  • Title of presentation:
  • Abstract (<100 word):
  • Preferable approximate dates (months) of presentation:
  • Preferred time of presentation:
    1. 17:00 UTC (this time corresponds to local times ~ 9 am at the Western coasts of USA to ~ 19 pm at edges of Eastern Europe)
    2. 09:00 UTC (this time corresponds to local times ~ 9 am at the western coasts of Europe and Africa to ~19 pm at the eastern coast of Australia)
    3. 01:00 UTC (this time corresponds to local times ~9 am at the western side of China and Australia to ~21 pm at the Eastern coast of USA)
  • Personal web-page link or a self-presentation up to 300 words.

With best wishes,
IAU Commission H1 OC

An artist's impression of what the Milky Way might look like seen from above. The colored rings show the rough extent of the fossil galaxy known as Heracles. The yellow dot shows the position of the Sun. Credit: Danny Horta-Darrington (Liverpool John Moores University), NASA/JPL-Caltech, and the SDSS

Congratulations to scientists working with data from the Sloan Digital Sky Surveys' Apache Point Observatory Galactic Evolution Experiment (APOGEE) who have discovered a "fossil galaxy" hidden in the depths of our own Milky Way.

More information can be found here.

Publication: Monthly Notices of the Royal Astronomical Society, 2020, Volume 500, Issue 1, pp.1385-1403

DOI: 10.1093/mnras/staa2987

From left to right: Roger Penrose, Andrea Ghez and Reinhard Genzel

Congratulations to our colleagues - the Nobel Prize in Physics 2020 winners - Roger Penrose "for the discovery that black hole formation is a robust prediction of the general theory of relativity", Reinhard Genzel and Andrea Ghez "for the discovery of a supermassive compact object at the centre of our galaxy".

More information can be found here.

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