We present a survey of star clusters in the halo of IC 10, a starburst galaxy in the Local Group based on Subaru R band images and NOAO Local Group Survey UBVRI images. We find five new star clusters. All these star clusters are located far from the center of IC 10, while previously known star clusters are mostly in the main body. Interestingly the distribution of these star clusters shows an asymmetrical structure elongated along the east and south-west direction. We derive UBVRI photometry of 66 star clusters including these new star clusters as well as previously known star clusters. Ages of the star clusters are estimated from the comparison of their UBVRI spectral energy distribution with the simple stellar population models. We find that the star clusters in the halo are all older than 1 Gyr, while those in the main body have various ages from very young (several Myr) to old (>1 Gyr). The young clusters (<10 Myr) are mostly located in the Hα emission regions and are concentrated on a small region at 2' in the south-east direction from the galaxy center, while the old clusters are distributed in a wider area than the disk. Intermediate-age clusters (~100 Myr) are found in two groups. One is close to the location of the young clusters and the other is at ~4' from the location of the young clusters. The latter may be related with past merger or tidal interaction.
Post-starburst (or "E+A") galaxies trace the fastest and most dramatic processes in galaxy evolution. Recent work studying the evolution of galaxies through this phase have revealed insights on how galaxies undergo structural and stellar population changes as well as the role of various feedback mechanisms. In this review, I summarize recent work on identifying post-starburst galaxies; tracing the role of this phase through cosmic time; measuring stellar populations, on-going star formation, morphologies, kinematics, interstellar medium properties, and AGN activity; mechanisms to cause the rec…
The Cosmic Owl: Twin Active Collisional Ring Galaxies with Starburst Merging Front at $z=1.14$
Tsinghua University(清华大学);National Radio Astronomy Observatory(国家射电天文台);The University of Tokyo(东京大学);Kavli Institute for the Physics and Mathematics of the Universe (WPI)(宇宙物理与数学研究 Kavli 研究所(WPI));Center for Data-Driven Discovery, Kavli IPMU (WPI), UTIAS(数据驱动发现中心,Kavli IPMU(WPI),UTIAS);Aix Marseille Univ.(艾克斯马赛大学);CNRS(法国国家科学研究中心);CNES(法国国家空间研究中心);LAM(拉格朗日天体物理学实验室);European Southern Observatory(欧洲南方天文台)
The correspondence between galaxy major mergers and starburst activity is well-established observationally and in simulations of low redshift galaxies. However, the evolution of the properties of interactions and of the galaxies involved suggests that the starburst response of galaxies to merger events could vary across cosmic time. Using the VINTERGATAN cosmological zoom-in simulation of a Milky Way-like galaxy, we show here that starbursts, i.e. episodes of fast star formation, are connected with the onset of tidal compression, itself induced by mergers. However, this compression becomes str…
A Possible Protocluster of Galaxies Serendipitously Discovered in the Field of an Intermediate-Redshift Post-starburst Galaxy
Texas A&M University(德州农工大学);University of Pittsburgh(匹兹堡大学);Rochester Institute of Technology(罗切斯特理工学院);Princeton University(普林斯顿大学);University of Colorado, Boulder(科罗拉多大学博尔德分校)
We study the relation between stellar mass (M*) and star formation rate (SFR) for star-forming galaxies over approximately five decades in stellar mass (5.5 <~ log10(M*/Msun) <~ 10.5) at z ~ 3-6.5. This unprecedented coverage has been possible thanks to the joint analysis of blank non-lensed fields (COSMOS/SMUVS) and cluster lensing fields (Hubble Frontier Fields) which allow us to reach very low stellar masses. Previous works have revealed the existence of a clear bimodality in the SFR-M* plane with a star-formation Main Sequence and a starburst cloud at z ~ 4-5. Here we show that this bimoda…
We develop a new method to infer the temporal, geometric, and energetic properties of galaxy outflows, by combining stellar spectral modeling to infer starburst ages, and absorption lines to measure velocities. If winds are accelerated with time during a starburst event, then these two measurements enable us to solve for the wind radius, similarly to length scales and the Hubble parameter in Big Bang cosmology. This wind radius is the vital, but hard-to-constrain parameter in wind physics. We demonstrate the method using spectra of 87 starburst galaxies at z=0.05-0.44, finding that winds accel…
On the contribution of ULXs to stellar feedback: an intermediate mass black hole candidate and the population of ULXs in the low-metallicity starburst galaxy ESO 338-4
Green Pea galaxies are low-redshift starburst dwarf galaxies, with properties similar to those of the high-redshift galaxies that reionized the Universe. We report the first mapping of the spatial distribution of atomic hydrogen (HI) in and around a Green Pea, GP J0213+0056 at z=0.0399, using the Giant Metrewave Radio Telescope (GMRT). Like many Green Peas, GP J0213+0056 shows strong HI 21 cm emission in single-dish spectroscopy, strong Ly-alpha emission, and a high [OIII]$λ$5007/[OIII]$λ$3727 luminosity ratio, O32 $\approx$ 8.8, consistent with a high leakage of Lyman-continuum radiation. Our…
Galactic winds are essential to regulation of star formation in galaxies. To study the distribution and dynamics of molecular gas in a wind, we imaged the nearby starburst galaxy NGC 1482 in CO ($J=1\rightarrow0$) at a resolution of 1'' ($\approx100$ pc) using the Atacama Large Millimeter/submillimeter Array. Molecular gas is detected in a nearly edge-on disk with a radius of 3 kpc and a biconical outflow emerging from the central 1 kpc starburst and extending to at least 1.5 kpc perpendicular to the disk. In the outflow, CO gas is distributed approximately as a cylindrically symmetrical envel…
Detection of a high-redshift molecular outflow in a primeval hyperstarburst galaxy
我们报告了通过阿塔卡马大型毫米/亚毫米阵列(ALMA)探测到的高激发水跃迁(H $_2$ O $4_{2,3}-4_{1,4}$和H $_2$ O $3_{3,0}-3_{2,1}$)的吸收,在星爆星系SPT 0346 -52($z=5.656$)中发现了一个高红移的大质量分子外流。宿主星系是高红移(恒星形成率; SFR $\sim3,600$ M $_\odot$年$^{-1}$)最强大的星暴星系之一,有一个极其紧凑的($\sim320$ pc)恒星形成区和一个恒星形成率面密度($Σ_{SFR}\sim5,500$ M $_{\odot}~$年$^{-1}~$ kpc $^{-2}$)比“最大”(即爱丁顿有限)星暴高5倍,这意味着一个高度瞬变的阶段。估计的流出速率为$\sim500$ M $_{\odot}$ year $^{-1}$,远低于SFR,这意味着在这种极端的恒星暴中,流出能力饱和,流出不再能够调节恒星的形成,导致失控的过程,恒星的形成将在不到3000万年的时间内耗尽所有可用的气体。最后,虽然之前对这个来源的运动学研究揭示了正在进行的重大合并的可能证据,但超紧凑的星暴和高激发水吸收的巧合表明这是一个被圆盘包围的单一星暴星系。
We report the detection of 23 OH+(1-0) absorption, emission, or P-Cygni-shaped lines and CO(9-8) emission lines in 18 Herschel-selected z=2-6 starburst galaxies with ALMA and NOEMA, taken as part of the Gas And Dust Over cosmic Time (GADOT) Galaxy Survey. We find that the CO(9-8) luminosity is higher than expected based on the far-infrared luminosity when compared to nearby star-forming galaxies. Together with the strength of the OH+ emission components, this may suggest that shock excitation of warm, dense molecular gas is more prevalent in distant massive dusty starbursts than in nearby star…
Post-starburst galaxies are crucial to disentangling the effect of star formation and quenching on galaxy demographics. They comprise, however, a heterogeneous population of objects, described in numerous ways. To obtain a well-defined and uncontaminated sample, we take advantage of spatially resolved spectroscopy to construct an unambiguous sample of E + A galaxies - post-starburst systems with no observed ongoing star formation. Using data from the Mapping Nearby Galaxies at Apache Point Observatory (MaNGA) Survey, in the fourth generation of the Sloan Digital Sky Survey (SDSS-IV), we have i…
Sparks II: Panchromatic SED modeling and galaxy physical properties across the starburst to post-starburst sequence
Kavli Institute for Particle Astrophysics & Cosmology, Stanford University(斯坦福大学卡弗里粒子天体物理与宇宙学研究所);Center for Decoding the Universe, Stanford University(斯坦福大学解码宇宙中心);Department of Astrophysical Sciences, Princeton University(普林斯顿大学天体物理科学系);Department of Astronomy and Astrophysics, University of California Santa Cruz(加州大学圣克鲁兹分校天文与天体物理系);Kavli Institute for the Physics and Mathematics of the Universe (Kavli IPMU)(宇宙物理与数学卡弗里研究所);Division of Science, National Astronomical Observatory of Japan(日本国立天文台科学部);Max-Planck-Institut für extraterrestrische Physik(马克斯·普朗克地外物理学研究所)
Cosmic rays from the nearby starburst galaxy NGC 253: the effect of a low luminosity active galactic nucleus
NGC 253是一个邻近的星暴星系,位于玉夫座星系群中,距离3.5 Mpc,一些作者认为它是宇宙射线加速到超高能量的潜在地点。它的核心区域被气体和尘埃严重遮蔽,这使得我们无法确定该星系是否拥有一个与星暴共存的超大质量黑洞。在文献中已经提出了一些来源作为活性核的候选者。在这项工作中,我们的目标是确定的影响,一个超大质量黑洞在NGC 253的核可能对宇宙射线加速的存在。有了这个目标,我们模拟的吸积流到假定的活动核,我们评估的可行性粒子加速的黑洞发电机机制。作为一个副产品,我们探索的吸积流中的非热粒子的星系的高能量发射的潜在贡献。我们发现,在三个最可能的核候选者,吸积流的排放将抑制黑洞发电机机制。为了完全排除NGC 253中一个假定的核可能对宇宙射线加速产生的影响,需要更好地澄清该核的真实性质。