Gaseous nebulae and massive stars in the giant H I ring in Leo
Gaseous nebulae and massive stars in the giant H I ring in Leo
复制标题
狮子座巨型 HI 环中的气态星云和大质量恒星
DOI：
--
复制
发表时间：
2021
影响因子：
6.5
通讯作者：
G. Venturi
中科院分区：
文献类型：
--
作者：
E. Corbelli;F. Mannucci;D. Thilker;G. Cresci;G. Venturi
上下文狮子座环是当地宇宙中最大的氢云，其化学丰度最近被确定接近或高于太阳值。这一发现与之前认为戒指起源于原始的说法不一致。这些气体在星系盘中预先富集并被潮汐剥离，无法在星系际空间有效地形成恒星。
目标。利用Hα发射和对它的极其微弱的光学对应物的多波长分析，我们研究了狮子座环中星星的形成过程和恒星群体的缓慢积累，这些恒星群体可能形成弥散的富含金属的矮星系。
方法.我们绘制了星云线在三个密集的H I团块和补充的数据与档案恒星连续观测星系演化探测器和哈勃太空望远镜，以及人口合成模型。
结果我们检测到稀疏的人口的恒星在主体的环，个别年轻的恒星大规模的O 7型供电的一些H II地区。环中的平均恒星形成率密度约为10−5 M <$yr−1 kpc−2，并伴随着几百秒差距大小的局部爆发，其中500−1000 M <$yr的松散恒星协偶而会有大质量的异常值。星云区域的远紫外线与Hα辐射的比率意味着200万~ 700万年前的恒星爆发。环中的局部氢气体密度和恒星形成率之间的关系与矮星和外盘中的气体耗尽时间长达100 Gyr的情况相似。我们在一个致密而微弱的Hα区发现了一个候选行星状星云，其[OIII]/Hα谱线增强，这与估计的环平均恒星表面亮度一致。在最明亮和最年轻的H II区域周围，存在一个1 kpc的部分环，发出微弱的Hα线，这表明局部冲击可能会触发未来的恒星形成地点。
Context. Chemical abundances in the Leo ring, the largest H I cloud in the local Universe, have recently been determined to be close to or above Solar values. This is a finding that is incompatible with prior claims that the ring was primordial in origin. The gas, pre-enriched in a galactic disk and tidally stripped, did not manage to efficiently form stars in the intergalactic space.
Aims. Using Hα emission and a multi-wavelengths analysis of its extremely faint optical counterpart, we investigate the process of star formation and the slow build-up of a stellar population that could form diffuse and metal-rich dwarf galaxies in the Leo ring.
Methods. We mapped nebular lines in three dense H I clumps and complemented the data with archival stellar continuum observations from the Galaxy Evolution Explorer and the Hubble Space Telescope, as well as with population synthesis models.
Results. We detect a sparse population of stars in the main body of the ring, with individual young stars as massive as O7-types powering some H II regions. The average star-formation rate density in the ring is on order of 10−5 M⊙ yr−1 kpc−2 and proceeds with local bursts a few hundred parsecs in size, where loose stellar associations of 500−1000 M⊙ occasionally host massive outliers. The far ultraviolet-to-Hα emission ratio in nebular regions implies recent stellar bursts, from 2 to 7 Myr ago. The relation between the local H I gas density and the star-formation rate in the ring is similar to what is found in dwarfs and outer disks with gas depletion times as long as 100 Gyr. We find a candidate planetary nebula in a compact and faint Hα region with [OIII]/Hα line enhancement, which is consistent with the estimated mean stellar surface brightness of the ring. The presence of a 1 kpc partial ring that is emitting weak Hα lines around the brightest and youngest H II region suggests that local shocks might triggers future star-forming sites.
登录
查看更多内容
DOI：
10.3847/1538-4365/aaa8e5
发表时间：
2018-01
期刊：
The Astrophysical Journal Supplement Series
影响因子：
--
作者：
E. Sabbi;D. Calzetti;L. Úbeda;A. Adamo;M. Cignoni;D. Thilker;A. Aloisi;B. Elmegreen;D. Elmegreen;D. Gouliermis;D. Gouliermis;E. Grebel;M. Messa;L. J. Smith;M. Tosi;A. Dolphin;J. E. Andrews;G. Ashworth;S. Bright;T. Brown;R. Chandar;C. Christian;G. C. Clayton;D. Cook;D. Cook;Daniel A. Dale;S. D. Mink;C. Dobbs;A. S. Evans;A. S. Evans;M. Fumagalli;J. S. Gallagher;K. Grasha;A. Herrero;A. Herrero;D. Hunter;Kelsey E. Johnson;L. Kahre;R. Kennicutt;Hwihyun Kim;M. Krumholz;Janice C. Lee;D. Lennon;C. Martin;P. Nair;A. Nota;G. Ostlin;A. Pellerin;J. Prieto;M. Regan;J. Ryon;E. Sacchi;E. Sacchi;D. Schaerer;D. Schiminovich;F. Shabani;S. V. Dyk;R. Walterbos;B. Whitmore;A. Wofford
通讯作者：
E. Sabbi;D. Calzetti;L. Úbeda;A. Adamo;M. Cignoni;D. Thilker;A. Aloisi;B. Elmegreen;D. Elmegreen;D. Gouliermis;D. Gouliermis;E. Grebel;M. Messa;L. J. Smith;M. Tosi;A. Dolphin;J. E. Andrews;G. Ashworth;S. Bright;T. Brown;R. Chandar;C. Christian;G. C. Clayton;D. Cook;D. Cook;Daniel A. Dale;S. D. Mink;C. Dobbs;A. S. Evans;A. S. Evans;M. Fumagalli;J. S. Gallagher;K. Grasha;A. Herrero;A. Herrero;D. Hunter;Kelsey E. Johnson;L. Kahre;R. Kennicutt;Hwihyun Kim;M. Krumholz;Janice C. Lee;D. Lennon;C. Martin;P. Nair;A. Nota;G. Ostlin;A. Pellerin;J. Prieto;M. Regan;J. Ryon;E. Sacchi;E. Sacchi;D. Schaerer;D. Schiminovich;F. Shabani;S. V. Dyk;R. Walterbos;B. Whitmore;A. Wofford
模拟大质量恒星的紫外线辐射反馈。
DOI：
10.3847/1538-4357/ab3d3d
发表时间：
2019
期刊：
The Astrophysical Journal
影响因子：
--
作者：
Kim, Jeong-Gyu;Kim, Woong-Tae;Ostriker, Eve C.
通讯作者：
Ostriker, Eve C.
影响因子：
6.5
作者：
M. Boquien;P. Duc;J. Braine;E. Brinks;U. Lisenfeld;V. Charmandaris
通讯作者：
M. Boquien;P. Duc;J. Braine;E. Brinks;U. Lisenfeld;V. Charmandaris
DOI：
10.1088/0004-6256/140/5/1194
发表时间：
2010-07
期刊：
The Astronomical Journal
影响因子：
--
作者：
F. Bigiel;A. Leroy;F. Walter;L. Blitz;E. Brinks;W. D. Blok;B. M. U. Berkeley;Mpia Heidelberg;Nrao;U. Hertfordshire;U. C. Town;C. Observatories
通讯作者：
F. Bigiel;A. Leroy;F. Walter;L. Blitz;E. Brinks;W. D. Blok;B. M. U. Berkeley;Mpia Heidelberg;Nrao;U. Hertfordshire;U. C. Town;C. Observatories