分类： 天文学 >> 天文学 提交时间： 2023-02-19
Guochao Sun
Tzu-Ching Chang
Bade D. Uzgil
Jamie Bock
Charles M. Bradford
Victoria Butler
Tessalie Caze-Cortes
Yun-Ting Cheng
Asantha Cooray
Abigail T. Crites
Steve Hailey-Dunsheath
Nick Emerson
Clifford Frez
Benjamin L. Hoscheit
Jonathon R. Hunacek
Ryan P. Keenan
Chao-Te Li
Paolo Madonia
Daniel P. Marrone
Lorenzo Moncelsi
摘要： Line intensity mapping (LIM) provides a unique and powerful means to probe cosmic structures by measuring the aggregate line emission from all galaxies across redshift. The method is complementary to conventional galaxy redshift surveys that are object-based and demand exquisite point-source sensitivity. The Tomographic Ionized-carbon Mapping Experiment (TIME) will measure the star formation rate (SFR) during cosmic reionization by observing the redshifted [CII] 158$\mu$m line ($6 \lesssim z \lesssim 9$) in the LIM regime. TIME will simultaneously study the abundance of molecular gas during the era of peak star formation by observing the rotational CO lines emitted by galaxies at $0.5 \lesssim z \lesssim 2$. We present the modeling framework that predicts the constraining power of TIME on a number of observables, including the line luminosity function, and the auto- and cross-correlation power spectra, including synergies with external galaxy tracers. Based on an optimized survey strategy and fiducial model parameters informed by existing observations, we forecast constraints on physical quantities relevant to reionization and galaxy evolution, such as the escape fraction of ionizing photons during reionization, the faint-end slope of the galaxy luminosity function at high redshift, and the cosmic molecular gas density at cosmic noon. We discuss how these constraints can advance our understanding of cosmological galaxy evolution at the two distinct cosmic epochs for TIME, starting in 2021, and how they could be improved in future phases of the experiment.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Minghao Yue
Jinyi Yang
Xiaohui Fan
Feige Wang
Justin Spilker
Iskren Y. Georgiev
Charles R. Keeton
Katrina C. Litke
Daniel P. Marrone
Fabian Walter
Ran Wang
Xue-Bing Wu
Bram P. Venemans
Ann Zabludoff
摘要： We report ALMA observations of the dust continuum and {\cii} emission of the host galaxy of J0439+1634, a gravitationally lensed quasar at $z=6.5$. Gravitational lensing boosts the source-plane resolution to $\sim0\farcs15$ $(\sim0.8\text{ kpc})$. The lensing model derived from the ALMA data is consistent with the fiducial model in \citet{fan19} based on {\it HST} imaging. The host galaxy of J0439+1634 can be well-fitted by a S\'ersic profile consistent with an exponential disk, both in the far-infrared (FIR) continuum and the {\cii} emission. The overall magnification is $4.53\pm0.05$ for the continuum and $3.44\pm0.05$ for the {\cii} line. The host galaxy of J0439+1634 is a compact ultra-luminous infrared galaxy, with a total star formation rate (SFR) of $1.56\times10^{3}M_\odot/\text{year}$ after correcting for lensing and an effective radius of $0.74$ kpc. The resolved regions in J0439+1634 follow the ``{\cii} deficit," where the {\cii}-to-FIR ratio decreases with FIR surface brightness. The reconstructed velocity field of J0439+1634 appears to be rotation-like. The maximum line-of-sight rotation velocity of 130 km/s at a radius of 2 kpc. However, our data cannot be fit by an axisymmetric thin rotating disk, and the inclination of the rotation axis, $i$, remains unconstrained. We estimate the dynamical mass of the host galaxy to be $7.9\sin^{-2}(i)\times10^{9}M_\odot$. J0439+1634 is likely to have a high gas-mass fraction and an oversized SMBH compared to local relations. The SFR of J0439+1634 reaches the maximum possible values, and the SFR surface density is close to the highest value seen in any star-forming galaxy currently known in the universe.
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