分类： 天文学 >> 天文学 提交时间： 2023-02-19
Xuheng Ding
Masafusa Onoue
John D. Silverman
Yoshiki Matsuoka
Takuma Izumi
Michael A. Strauss
Knud Jahnke
Irham Taufik Andika
Kentaro Aoki
Shunsuke Baba
Rebekka Bieri
Sarah E. I. Bosman
Anna-Christina Eilers
Seiji Fujimoto
Melanie Habouzit
Zoltan Haiman
Masatoshi Imanishi
Kohei Inayoshi
Kazushi Iwasawa
Nobunari Kashikawa
摘要： The existence of high-redshift supermassive black holes (SMBHs) -- shining brightly as quasars during the first billion years of our universe -- presents a conundrum in astrophysics. A broad variety of physical mechanisms have been proposed for the formation and rapid growth of these early SMBHs. Promising diagnostics are the relative properties of the black hole and its host galaxy. However, up to now, the detection of stars in quasar host galaxies has been elusive beyond $z>2$, even with deep HST observations. Here, we report the first detections of the stellar component of the host galaxies of two relatively low-luminosity quasars at $z>6$ observed with JWST using NIRCam. After modeling and subtracting the glare from the quasar itself, we find that the host galaxies are massive (stellar mass of $2.5\times$ and $6.3\times10^{10}$ M$_{\odot}$), compact, and disk-like. Unlike most SMBHs in the nearby universe, these quasars are displaced from the centers of their host galaxies in the rest-frame optical, in one case by $0.9$ kpc. These first positive detections of quasar hosts at $z>6$ are a pivotal milestone; we can now assess the stellar environment along with star formation and black hole accretion to determine the physical conditions that govern the formation and evolution of the first SMBHs.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Xuheng Ding
John D. Silverman
Tommaso Treu
Junyao Li
Aklant K. Bhowmick
Nicola Menci
Marta Volonteri
Laura Blecha
Tiziana Di Matteo
Yohan Dubois
摘要： We carry out a comparative analysis of the relation between the mass of
supermassive black holes (BHs) and the stellar mass of their host galaxies at
$0.2
分类： 天文学 >> 天文学 提交时间： 2023-02-19
J. K. Jang
Sukyoug K. Yi
Yohan Dubois
Jinsu Rhee
Christophe Pichon
Taysun Kimm
Julien Devriendt
Marta Volonteri
Sugata Kaviraj
Sebastien Peirani
Sree Oh
Scott Croom
摘要： Based on the recent advancements in the numerical simulations of galaxy formation, we anticipate the achievement of realistic models of galaxies in the near future. Morphology is the most basic and fundamental property of galaxies, yet observations and simulations still use different methods to determine galaxy morphology, making it difficult to compare them. We hereby perform a test on the recent NewHorizon simulation which has spatial and mass resolutions that are remarkably high for a large-volume simulation, to resolve the situation. We generate mock images for the simulated galaxies using SKIRT that calculates complex radiative transfer processes in each galaxy. We measure morphological indicators using photometric and spectroscopic methods following observer's techniques. We also measure the kinematic disk-to-total ratios using the Gaussian mixture model and assume that they represent the true structural composition of galaxies. We found that spectroscopic indicators such as $V/{\sigma}$ and ${\lambda}_{R}$ closely trace the kinematic disk-to-total ratios. In contrast, photometric disk-to-total ratios based on the radial profile fitting method often fail to recover the true kinematic structure of galaxies, especially for small galaxies. We provide translating equations between various morphological indicators.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Emanuele Paolo Farina
Jan-Torge Schindler
Fabian Walter
Eduardo Bañados
Frederick B. Davies
Roberto Decarli
Anna-Christina Eilers
Xiaohui Fan
Joseph F. Hennawi
Chiara Mazzucchelli
Romain A. Meyer
Benny Trakhtenbrot
Marta Volonteri
Feige Wang
Gabor Worseck
Jinyi Yang
Thales A. Gutcke
Bram P. Venemans
Sarah E. I. Bosman
Tiago Costa
摘要： We present measurements of black hole masses and Eddington ratios for a sample of 38 bright (M$_{1450}$ 6. Combined with deep ALMA observations of the [CII] 158 $\mu$m line from the quasar host galaxies and VLT/MUSE investigations of the extended Ly$\alpha$ halos, this study provides fundamental clues to models of the formation and growth of the first massive galaxies and black holes. Compared to local scaling relations, z > 5.7 black holes appear to be over-massive with respect to their host galaxies, and their accretion properties do not change with host galaxy morphology. Under the assumption that the kinematics of the T ~ 10$^4$ K gas, traced by the extended Ly$\alpha$ halos, are dominated by the gravitational potential of the dark matter halo, we report a similar relation between the black hole mass and circular velocity to the one reported for z ~ 0 galaxies. These results paint a picture where the first supermassive black holes reside in massive halos at z > 6 and lead the first stages of galaxy formation by rapidly growing in mass with a duty cycle of order unity. However, this duty cycle needs to drastically drop towards lower redshifts, while the host galaxies continue forming stars at a rate of hundreds of solar masses per year, sustained by the large reservoirs of cool gas surrounding them.
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