OGHReS: star formation in the outer Galaxy II (ℓ = 180–280°)
ABSTRACT The Outer Galaxy High-Resolution Survey (OGHReS) covers 100 square degrees ($180^{\circ }< \ell < 280^{\circ }$) in the (2–1) transitions of three CO-isotopologues. We use the spectra to refine the velocities and physical properties to 6706 Hi-GAL clumps located in the OGHReS region. In a previous paper, we analysed 3584 clumps between $\ell = 250^{\circ }$ and $280^{\circ }$. Here, we cover a further 3122 clumps ($180^{\circ }< \ell < 250^{\circ }$) and determine reliable velocities for 2781 of these, finding good agreement with the previously assigned velocities ($\sim$80 per cent within 5 km s$^{-1}$). We update velocities for 288 clumps and provide new values for an additional 411. Combining these with the previous results, we have velocities and physical properties for 6193 clumps (92.3 per cent). The 422 non-detections are low surface density clumps or likely contamination by evolved stars and galaxies. Key findings: (i) improved correlation between clumps and spiral arm loci and the discovery of clumps beyond the outer arm supports the existence of a new spiral structure; (ii) decreasing trend in the $L/M$-ratio consistent with less high-mass star formation in the outer Galaxy; (iii) increase in the star formation fraction in the outer Galaxy, suggesting that more clumps are forming stars despite their lower mass; (iv) discrepancies in velocity assignments across different surveys that could affect $\sim$10000 clumps, especially in the fourth quadrant.
Authors
- Yan Sun (ORCID: https://orcid.org/0000-0002-3904-1622)
- Dario Colombo (ORCID: https://orcid.org/0000-0001-6498-2945)
- C. König (ORCID: https://orcid.org/0000-0001-8032-9874)
- S. Neupane (ORCID: https://orcid.org/0000-0001-9596-9938)
- David J. Eden (ORCID: https://orcid.org/0000-0002-5881-3229)
- S. Leurini (ORCID: https://orcid.org/0000-0003-1014-3390)
- A. Giannetti (ORCID: https://orcid.org/0000-0003-3869-6501)
- A. Karska (ORCID: https://orcid.org/0000-0001-8913-925X)
- W.-J. Kim (ORCID: https://orcid.org/0000-0003-0364-6715)
- K. R. Neralwar (ORCID: https://orcid.org/0000-0003-3205-4460)
- M. Figueira (ORCID: https://orcid.org/0000-0002-9068-6215)
- A. Y. Yang (ORCID: https://orcid.org/0000-0003-4546-2623)
- J. Brand (ORCID: https://orcid.org/0000-0003-1615-9043)
- F. Wyrowski (ORCID: https://orcid.org/0000-0003-4516-3981)
- V. S. Veena (ORCID: https://orcid.org/0000-0002-0801-8550)
- J. S. Urquhart (ORCID: https://orcid.org/0000-0002-1605-8050)
- Ivana I. Grozdanova (ORCID: https://orcid.org/0009-0006-6327-0595)
- Min-Young Lee (ORCID: https://orcid.org/0000-0002-9888-0784)
- Zhong‐Jie Jiang (ORCID: https://orcid.org/0000-0002-5612-3128)
- T. J. T. Moore
- E. Dann (ORCID: https://orcid.org/0009-0001-9861-3619)
Institutions
- University of Bonn (DE)
- University of Cologne (DE)
- Chinese Academy of Sciences (CN)
- University of Kent (GB)
- Armagh Observatory & Planetarium (GB)
- Korea Astronomy and Space Science Institute (KR)
- Purple Mountain Observatory (CN)
- Institute of Physics (AZ)
- Istituto di Radioastronomia di Bologna (IT)
- Nicolaus Copernicus Astronomical Center (PL)
- Osservatorio Astronomico di Cagliari (IT)
- Max Planck Institute for Radio Astronomy (DE)
- National Astronomical Observatories (CN)
- University of Warsaw (PL)
- University of Bath (GB)
- Liverpool John Moores University (GB)
Publication Details
- Journal
- Monthly Notices of the Royal Astronomical Society
- Published
- 2025-04-29
- DOI
- https://doi.org/10.1093/mnras/staf665
- Citations
- 3
- Primary Topic
- Astrophysics and Star Formation Studies
- Type
- article
- Field-Weighted Citation Impact
- 3.46