• Rutherford’s Atomic Nucleus versus Landau’s Gigantic Nucleus: Does Nature favor flavor symmetry?

    分类: 物理学 >> 核物理学 分类: 物理学 >> 地球物理学、天文学和天体物理学 提交时间: 2024-02-29

    摘要: It is hypothesized that, though atomic nuclei are made of nucleons, strongly interacting matter with baryon number from $A simeq 10^{3-9}$ to $ sim 10^{57}$ would be composed of strangeons if Nature favors always the flavor symmetry of quarks.According to that logic, strangeon matter with $A sim 10^{57}$ could manifest in the form of pulsar-like compact stars, and multi-messenger observations with advanced facilities (e.g., China’s FAST) could eventually provide a disproof/proof.It is worth emphasizing that this point of view, based on established “old physics”, may have particular consequences for understanding our material world, for both normal luminous matter and the dark sector.

  • The interstellar medium distribution, gas kinematics, and system dynamics of the far-infrared luminous quasar SDSS J2310+1855 at $z=6.0$

    分类: 天文学 >> 天文学 提交时间: 2023-02-21

    摘要: We present Atacama Large Millimeter/submillimeter Array (ALMA) sub-kiloparsec- to kiloparsec-scale resolution observations of the [C ii], CO (98), and OH+ (1101) lines along with their dust continuum emission toward the far-infrared (FIR) luminous quasar SDSS J231038.88+185519.7 at z = 6.0031, to study the interstellar medium distribution, the gas kinematics, and the quasar-host system dynamics. We decompose the intensity maps of the [C ii] and CO (98) lines and the dust continuum with two-dimensional elliptical Srsic models. The [C ii] brightness follows a flat distribution with a Srsic index of 0.59. The CO (98) line and the dust continuum can be fit with an unresolved nuclear component and an extended Srsic component with a Srsic index of 1, which may correspond to the emission from an active galactic nucleus dusty molecular torus and a quasar host galaxy, respectively. The different [C ii] spatial distribution may be due to the effect of the high dust opacity, which increases the FIR background radiation on the [C ii] line, especially in the galaxy center, significantly suppressing the [C ii] emission profile. The dust temperature drops with distance from the center. The effective radius of the dust continuum is smaller than that of the line emission and the dust mass surface density, but is consistent with that of the star formation rate surface density. This may indicate that the dust emission is a less robust tracer of the dust and gas distribution but is a decent tracer of the obscured star formation activity. The OH+ (1101) line shows a P-Cygni profile with an absorption at 400 km/s, which may indicate an outflow with a neutral gas mass of (6.2 1.2) 108 M along the line of sight. We employed a three-dimensional tilted ring model to fit the [C ii] and CO (98) data cubes. The two lines are both rotation dominated and trace identical disk geometries and gas motions. This suggest that the [C ii] and CO (98) gas are coplanar and corotating in this quasar host galaxy. The consistent circular velocities measured with [C ii] and CO (98) lines indicate that these two lines trace a similar gravitational potential. We decompose the circular rotation curve measured from the kinematic model fit to the [C ii] line into four matter components (black hole, stars, gas, and dark matter). The quasar-starburst system is dominated by baryonic matter inside the central few kiloparsecs. We constrain the black hole mass to be 2.97+0.51 0.77 109 M ; this is the first time that the dynamical mass of a black hole has been measured at z 6. This mass is consistent with that determined using the scaling relations from quasar emission lines. A massive stellar component (on the order of 109 M ) may have already existed when the Universe was only 0.93 Gyr old. The relations between the black hole mass and the baryonic mass of this quasar indicate that the central supermassive black hole may have formed before its host galaxy.