A Comparison between Nuclear Ring Star Formation in LIRGs and in Normal Galaxies with the Very Large Array
A Comparison between Nuclear Ring Star Formation in LIRGs and in Normal Galaxies with the Very Large Array
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DOI：
10.3847/1538-4357/ac05c2
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发表时间：
2021-07
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通讯作者：
Y. Song;S. Linden;A. Evans;L. Barcos-Muñoz;G. Privon;I. Yoon;E. Murphy;K. Larson;T. D'iaz-Santos;L. Armus;J. Mazzarella;J. Howell;H. Inami;N. Torres-Albà;U. V.;V. Charmandaris;E. Momjian;J. McKinney;D. Astronomy;U. Virginia;D. Astronomy;U. O. Massachusetts;National Radio Astronomy Observatory;Charlottesville;Ipac;Institute of Astrophysics;F. F. Research-F.;Technology-Hellas N'ucleo de Astronom'ia de la Facultad de Ingenier' Ciencias-Technology-Hellas-N'ucleo-de-Astronom'ia-de-la-de-2264857848;Universidad Diego Portales;Chinese Center for Antarctic Astronomy;National Astronomical Observatories;Hiroshima Astrophysical Science Center;H. University;D. Astronomy;Clemson University;D. O. Physics;Astronomy;U. California;Irvine;U. Crete;Socorro
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作者：
Y. Song;S. Linden;A. Evans;L. Barcos-Muñoz;G. Privon;I. Yoon;E. Murphy;K. Larson;T. D'iaz-Santos;L. Armus;J. Mazzarella;J. Howell;H. Inami;N. Torres-Albà;U. V.;V. Charmandaris;E. Momjian;J. McKinney;D. Astronomy;U. Virginia;D. Astronomy;U. O. Massachusetts;National Radio Astronomy Observatory;Charlottesville;Ipac;Institute of Astrophysics;F. F. Research-F.;Technology-Hellas N'ucleo de Astronom'ia de la Facultad de Ingenier' Ciencias-Technology-Hellas-N'ucleo-de-Astronom'ia-de-la-de-2264857848;Universidad Diego Portales;Chinese Center for Antarctic Astronomy;National Astronomical Observatories;Hiroshima Astrophysical Science Center;H. University;D. Astronomy;Clemson University;D. O. Physics;Astronomy;U. California;Irvine;U. Crete;Socorro
核环是研究强烈星星形成的绝佳实验室。我们目前的研究结果的核恒星形成环在附近的5个正常星系的星星形成射电巡天（SFRS）和4个本地LIRG从大天文台全天LIRG巡天在次千秒差距分辨率使用甚大阵高频射电连续观测。我们发现，核环星星形成（NRSF）贡献了LIRGs的总星星形成的49%-60%，而正常星系的7%-40%。我们描述了这些环中总共57个独立的恒星形成区，并发现在测量的10-200 pc大小的LIRG中，NRSF区的星星形成率（SFR）和恒星形成率分别高达1.7 M yr−1和402 M yr−1 kpc−2，这比类似大小的正常星系中的NRSF区高出约10倍，与透镜状的高Z恒星形成区相当。在100-300 pc尺度下，我们估计在LIRGs的NRSF区域中，33 GHz处的热自由-自由发射对总射电连续谱发射的贡献很小（<50%），但在较小的物理尺度下可能存在较大的变化。最后，使用档案次千秒差距分辨率CO（J = 1-0）的正常星系和NGC 7469（LIRG）的核环的数据，我们发现一个大的分散在气体耗尽时间在类似的分子气体表面密度，这初步指向一个多模态的星星形成关系的次千秒差距尺度。
Nuclear rings are excellent laboratories for studying intense star formation. We present results from a study of nuclear star-forming rings in five nearby normal galaxies from the Star Formation in Radio Survey (SFRS) and four local LIRGs from the Great Observatories All-sky LIRG Survey at sub-kiloparsec resolutions using Very Large Array high-frequency radio continuum observations. We find that nuclear ring star formation (NRSF) contributes 49%–60% of the total star formation of the LIRGs, compared to 7%–40% for the normal galaxies. We characterize a total of 57 individual star-forming regions in these rings, and find that with measured sizes of 10–200 pc, NRSF regions in the LIRGs have star formation rate (SFR) and ΣSFR up to 1.7 M ⊙ yr−1 and 402 M ⊙ yr−1 kpc−2, respectively, which are about 10 times higher than in NRSF regions in the normal galaxies with similar sizes, and comparable to lensed high-z star-forming regions. At ∼100–300 pc scales, we estimate low contributions (<50%) of thermal free–free emission to total radio continuum emission at 33 GHz in the NRSF regions in the LIRGs, but large variations possibly exist at smaller physical scales. Finally, using archival sub-kiloparsec resolution CO (J = 1–0) data of nuclear rings in the normal galaxies and NGC 7469 (LIRG), we find a large scatter in gas depletion times at similar molecular gas surface densities, which tentatively points to a multimodal star formation relation on sub-kiloparsec scales.