OGHReS: star formation in the outer Galaxy II (l= 180 280)

J S Urquhart; C König; D. Colombo; A. Karska; A Giannetti; T. J.T. Moore; A Y Yang; F. Wyrowski; Y Sun; J Jiang; K R  Neralwar; David Eden; I Grozdanova; S Neupane; M Figueira; E Dann; V S Veena; W-J Kim; S Leurini; J Brand; M Y Lee

doi:10.1093/mnras/staf665

OGHReS: star formation in the outer Galaxy II (l= 180 280)

J S Urquhart, C König, D. Colombo, A. Karska, A Giannetti, T. J.T. Moore, A Y Yang, F. Wyrowski, Y Sun, J Jiang, K R Neralwar, David Eden, I Grozdanova, S Neupane, M Figueira, E Dann, V S Veena, W-J Kim, S Leurini, J BrandM Y Lee

Department of Physics

Research output: Contribution to journal › Article › peer-review

Abstract

The Outer Galaxy High-Resolution Survey (OGHReS) covers 100 square degrees (<![CDATA[$180^{\circ }< \ell) 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 and. Here, we cover a further 3122 clumps (<![CDATA[$180^{\circ }< \ell) and determine reliable velocities for 2781 of these, finding good agreement with the previously assigned velocities (80 per cent within 5 km s). 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 -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 10000 clumps, especially in the fourth quadrant. 2025 The Author(s).

Original language	English
Article number	staf665
Pages (from-to)	3105-3121
Number of pages	17
Journal	Monthly Notices of the Royal Astronomical Society
Volume	539
Issue number	4
Early online date	30 Apr 2025
DOIs	https://doi.org/10.1093/mnras/staf665
Publication status	Published - 30 Jun 2025

Data Availability Statement

The Hi-GAL catalogue used for this work can be found at http://vialactea.iaps.inaf.it/vialactea/public/ and the OGHReS catalogue used here can be found on CDS.

Funding

We thank the referee Michael G. Burton for their positive and timely response and for their comments and suggestions that have helped impro v e the clarity and readability of this work. We dedicate this work to Karl M. Menten, whose tireless mentorship, kindness, and open-hearted support profoundly shaped our scientific journeys and continues to inspire. We are very grateful for the continuous support provided by the APEX staff. We also extend our thanks for Davide Elia for useful discussions and clarifications for the Hi-GAL catalogue. JU acknowledges the support from the Chinese Academy of Sciences (CAS) in the form of a PIFI fellowship awarded to work with Prof. Zhibo Jiang and colleagues at the Purple Mountain Observ atory (MZ10007920240511600643). ZJ ackno wledges the support through the National Natural Science Foundation of China (NSFC, grant nos U2031202, 12373030, and 11873093). AK and MF acknowledge support from the Polish National Agency for Aca- demic Exchange grants nos BPN/BEK/2021/1/00319/DEC/1 and BPN/BEK/2023/1/00036/DEC/01, respecti vely. MF ackno wledges also support from the Polish National Science Centre via the grant no. UMO-2022/47/D/ST9/00419. ED, SN, MF, and DC gratefully acknowledges the Collaborative Research Center 1601 (SFB 1601 sub-projects A1, B1, and B3) funded by the Deutsche Forschungs- gemeinschaft (DFG, German Research Foundation) 500700252. ED is a member of the International Max Planck Research School (IMPRS) for Astronomy and Astrophysics at the Universities of Bonn and Cologne. WJK was supported by DLR/Verbundforschung Astronomie und Astrophysik grant 50 OR 2007. SL acknowledges support by the INAF PRIN 2019 grant ONSET. This research made use of ASTROPY 5 , a community-developed core PYTHON package for Astronomy (Astropy Collaboration 2013 , 2018 ), NUMPY (Harris et al. 2020 ) 6 , SCIPY (Virtanen et al. 2020 ) 7 , and MATPLOTLIB (Hunter 2007 ). 8 This document was prepared using the Overleaf web appli- cation, which can be found at www.overleaf.com . This research has made use of the VizieR catalogue, operated at CDS, Strasbourg, France. This publication is based on data acquired with the APEX. APEX is a collaboration between the Max-Planck-Institut f ur Radioas- tronomie, the European Southern Observatory, and the Onsala Space Observatory. The full version of Tables 1 and 2 are only available in elec- tronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.125.5) or via http:// cdsweb.u-strasbg.fr/ cgi-bin/ qcat?J/M NRAS/. We thank the referee Michael G. Burton for their positive and timely response and for their comments and suggestions that have helped improve the clarity and readability of this work. We dedicate this work to Karl M. Menten, whose tireless mentorship, kindness, and open-hearted support profoundly shaped our scientific journeys and continues to inspire. We are very grateful for the continuous support provided by the APEX staff. We also extend our thanks for Davide Elia for useful discussions and clarifications for the Hi-GAL catalogue. JU acknowledges the support from the Chinese Academy of Sciences (CAS) in the form of a PIFI fellowship awarded to work with Prof. Zhibo Jiang and colleagues at the Purple Mountain Observatory (MZ10007920240511600643). ZJ acknowledges the support through the National Natural Science Foundation of China (NSFC, grant nos U2031202,12373030, and 11873093). AK and MF acknowledge support from the Polish National Agency for Academic Exchange grants nos BPN/BEK/2021/1/00319/DEC/1 and BPN/BEK/2023/1/00036/DEC/01, respectively. MF acknowledges also support from the Polish National Science Centre via the grant no. UMO-2022/47/D/ST9/00419. ED, SN, MF, and DC gratefully acknowledges the Collaborative Research Center 1601 (SFB 1601 sub-projects A1, B1, and B3) funded by the Deutsche Forschungsgemeinschaft (DFG, German Research Foundation) \u2013 500700252. ED is a member of the International Max Planck Research School (IMPRS) for Astronomy and Astrophysics at the Universities of Bonn and Cologne. WJK was supported by DLR/Verbundforschung Astronomie und Astrophysik grant 50 OR 2007. SL acknowledges support by the INAF PRIN 2019 grant ONSET. This research made use of astropy , a community-developed core python package for Astronomy (Astropy Collaboration , ), numpy (Harris et al. ), scipy (Virtanen et al. ), and matplotlib (Hunter ).This document was prepared using the Overleaf web application, which can be found at www.overleaf.com . This research has made use of the VizieR catalogue, operated at CDS, Strasbourg, France.

Funders	Funder number
Polish National Agency for Aca- demic Exchange
Max-Planck-Institut f ur Radioas- tronomie
European Southern Observatory
Universities of Bonn and Cologne
International Max Planck Research School for Environmental, Cellular and Molecular Microbiology
NRAS
Deutsches Zentrum für Luft‑ und Raumfahrt
Istituto Nazionale di Astrofisica
National Natural Science Foundation of China	12373030, U2031202,12373030, U2031202, 11873093
Deutsche Forschungsgemeinschaft	500700252
Narodowa Agencja Wymiany Akademickiej	BPN/BEK/2021/1/00319/DEC/1, BPN/BEK/2023/1/00036/DEC/01
Verbundforschung Astronomie und Astrophysik	50 OR 2007
Chinese Diabetes Society	130.79.125.5
Narodowe Centrum Nauki	UMO-2022/47/D/ST9/00419, SFB 1601
Chinese Academy of Sciences	MZ10007920240511600643

Keywords

Galaxy: structure
ISM: molecules
infrared: stars
stars: formation
stars: protostars

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

Access to Document

10.1093/mnras/staf665Licence: CC BY

Cite this

Urquhart, J. S., König, C., Colombo, D., Karska, A., Giannetti, A., Moore, T. J. T., Yang, A. Y., Wyrowski, F., Sun, Y., Jiang, J., Neralwar, K. R., Eden, D., Grozdanova, I., Neupane, S., Figueira, M., Dann, E., Veena, V. S., Kim, W.-J., Leurini, S., ... Lee, M. Y. (2025). OGHReS: star formation in the outer Galaxy II (l= 180 280). Monthly Notices of the Royal Astronomical Society, 539(4), 3105-3121. Article staf665. https://doi.org/10.1093/mnras/staf665

Urquhart, JS, König, C, Colombo, D, Karska, A, Giannetti, A, Moore, TJT, Yang, AY, Wyrowski, F, Sun, Y, Jiang, J, Neralwar, KR, Eden, D, Grozdanova, I, Neupane, S, Figueira, M, Dann, E, Veena, VS, Kim, W-J, Leurini, S, Brand, J & Lee, MY 2025, 'OGHReS: star formation in the outer Galaxy II (l= 180 280)', Monthly Notices of the Royal Astronomical Society, vol. 539, no. 4, staf665, pp. 3105-3121. https://doi.org/10.1093/mnras/staf665

@article{7108a0c2ff3b468492a801f8c1aeb0ac,

title = "OGHReS: star formation in the outer Galaxy II (l= 180 280)",

abstract = "The Outer Galaxy High-Resolution Survey (OGHReS) covers 100 square degrees (<![CDATA[$180^{\circ }< \ell) 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 and. Here, we cover a further 3122 clumps (<![CDATA[$180^{\circ }< \ell) and determine reliable velocities for 2781 of these, finding good agreement with the previously assigned velocities (80 per cent within 5 km s). 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 -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 10000 clumps, especially in the fourth quadrant. 2025 The Author(s).",

keywords = "Galaxy: structure, ISM: molecules, infrared: stars, stars: formation, stars: protostars",

author = "Urquhart, {J S} and C K{\"o}nig and D. Colombo and A. Karska and A Giannetti and Moore, {T. J.T.} and Yang, {A Y} and F. Wyrowski and Y Sun and J Jiang and Neralwar, {K R} and David Eden and I Grozdanova and S Neupane and M Figueira and E Dann and Veena, {V S} and W-J Kim and S Leurini and J Brand and Lee, {M Y}",

year = "2025",

month = jun,

day = "30",

doi = "10.1093/mnras/staf665",

language = "English",

volume = "539",

pages = "3105--3121",

journal = "Monthly Notices of the Royal Astronomical Society",

issn = "0035-8711",

publisher = "Oxford University Press",

number = "4",

}

TY - JOUR

T1 - OGHReS

T2 - star formation in the outer Galaxy II (l= 180 280)

AU - Urquhart, J S

AU - König, C

AU - Colombo, D.

AU - Karska, A.

AU - Giannetti, A

AU - Moore, T. J.T.

AU - Yang, A Y

AU - Wyrowski, F.

AU - Sun, Y

AU - Jiang, J

AU - Neralwar, K R

AU - Eden, David

AU - Grozdanova, I

AU - Neupane, S

AU - Figueira, M

AU - Dann, E

AU - Veena, V S

AU - Kim, W-J

AU - Leurini, S

AU - Brand, J

AU - Lee, M Y

PY - 2025/6/30

Y1 - 2025/6/30

N2 - The Outer Galaxy High-Resolution Survey (OGHReS) covers 100 square degrees (<![CDATA[$180^{\circ }< \ell) 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 and. Here, we cover a further 3122 clumps (<![CDATA[$180^{\circ }< \ell) and determine reliable velocities for 2781 of these, finding good agreement with the previously assigned velocities (80 per cent within 5 km s). 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 -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 10000 clumps, especially in the fourth quadrant. 2025 The Author(s).

AB - The Outer Galaxy High-Resolution Survey (OGHReS) covers 100 square degrees (<![CDATA[$180^{\circ }< \ell) 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 and. Here, we cover a further 3122 clumps (<![CDATA[$180^{\circ }< \ell) and determine reliable velocities for 2781 of these, finding good agreement with the previously assigned velocities (80 per cent within 5 km s). 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 -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 10000 clumps, especially in the fourth quadrant. 2025 The Author(s).

KW - Galaxy: structure

KW - ISM: molecules

KW - infrared: stars

KW - stars: formation

KW - stars: protostars

UR - http://www.scopus.com/inward/record.url?scp=105004768302&partnerID=8YFLogxK

U2 - 10.1093/mnras/staf665

DO - 10.1093/mnras/staf665

M3 - Article

SN - 0035-8711

VL - 539

SP - 3105

EP - 3121

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 4

M1 - staf665

ER -

OGHReS: star formation in the outer Galaxy II (l= 180 280)

Abstract

Data Availability Statement

Funding

Keywords

ASJC Scopus subject areas

Access to Document

Other files and links

Fingerprint

Cite this