分类： 天文学 >> 天文学 提交时间： 2023-02-19
Yunjing Wu
Zheng Cai
Fengwu Sun
Fuyan Bian
Xiaojing Lin
Zihao Li
Mingyu Li
Franz E. Bauer
Eiichi Egami
Xiaohui Fan
Jorge González-López
Jianan Li
Feige Wang
Jinyi Yang
Shiwu Zhang
Siwei Zou
摘要： Spiral arms serve crucial purposes in star formation and galaxy evolution. In this paper, we report the identification of A2744-DSG-$z3$, a dusty, multiarm spiral galaxy at $z=3.059$ using the James Webb Space Telescope (JWST) NIRISS imaging and grism spectroscopy. A2744-DSG-$z3$ was discovered as a gravitationally lensed sub-millimeter galaxy with ALMA. This is the most distant stellar spiral structure seen thus far, consistent with cosmological simulations which suggest $z\approx3$ as the epoch when spirals emerge. Thanks to the gravitational lensing and excellent spatial resolution of JWST, the spiral arms are resolved with a spatial resolution of $\approx290$\,pc. Based on SED fitting, the spiral galaxy has a de-lensed star formation rate of $85\pm30 \ M_{\odot}$ yr$^{-1}$, and a stellar mass of $\approx10^{10.6}M_{\odot}$, indicating that A2744-DSG-$z3$ is a main-sequence galaxy. After fitting the spiral arms, we find a stellar effective radius ($R_{e, \rm{star}}$) of $5.0\pm1.5$ kpc. Combing with ALMA measurements, we find that the effective radii ratio between dust and stars is $\approx0.4$, similar to {those} of massive SFGs at $z\sim2$, indicating a compact dusty core in A2744-DSG-$z3$. Moreover, this galaxy appears to be living in a group environment: including A2744-DSG-$z3$, at least three galaxies at $z=3.05 - 3.06$ {are} spectroscopically confirmed by JWST/NIRISS and ALMA, residing within a lensing-corrected projected scale of $\approx 70$ kpc. This, along with the asymmetric brightness profile, further suggests that the spiral arms may be triggered by minor merger events at $z\gtrsim3$.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Jianrui Li
Bjorn H. C. Emonts
Zheng Cai
J. Xavier Prochaska
Ilsang Yoon
Matthew D. Lehnert
Shiwu Zhang
Yunjing Wu
Jianan Li
Mingyu Li
Mark Lacy
Montserrat Villar-Martín
摘要： The link between the circum-galactic medium (CGM) and the stellar growth of massive galaxies at high-$z$ depends on the properties of the widespread cold molecular gas. As part of the SUPERCOLD-CGM survey (Survey of Protocluster ELANe Revealing CO/\ci\ in the Ly$\alpha$-Detected CGM), we present the radio-loud QSO Q1228+3128 at $z=2.2218$, which is embedded in an enormous Ly$\alpha$ nebula. ALMA+ACA observations of CO(4-3) reveal both a massive molecular outflow, and a more extended molecular gas reservoir across $\sim$100 kpc in the CGM each containing a mass of M$_{\rm H2}$\,$\sim$\,4$-$5\,$\times$\,10$^{10}$ M$_{\odot}$. The outflow and molecular CGM are aligned spatially, along the direction of an inner radio jet. After re-analysis of Ly$\alpha$ data of Q1228+3128 from the Keck Cosmic Web Imager, we found that the velocity of the extended CO agrees with the redshift derived from the Ly$\alpha$ nebula and the bulk velocity of the massive outflow. We propose a scenario where the radio source in Q1228+3128 is driving the molecular outflow and perhaps also enriching or cooling the CGM. In addition, we found that the extended CO emission is nearly perpendicular to the extended Ly$\alpha$ nebula spatially, indicating that the two gas phases are not well mixed, and possibly even represent different phenomena (e.g., outflow vs. infall). Our results provide crucial evidence in support of predicted baryonic recycling processes that drive the early evolution of massive galaxies.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Yunjing Wu
Zheng Cai
Marcel Neeleman
Kristian Finlator
Shiwu Zhang
J. Xavier Prochaska
Ran Wang
Bjorn H.
C Emonts
Xiaohui Fan
Laura C. Keating
Feige Wang
Jinyi Yang
Joseph F. Hennawi
Junxian Wang
摘要： The physical and chemical properties of the circumgalactic medium (CGM) at $z\gtrsim6$ have been studied successfully through the absorption in the spectra of background Quasi-Stellar Objects (QSOs). One of the most crucial questions is to investigate the nature and location of the source galaxies that give rise to these early metal absorbers. Theoretical models suggest that momentum-driven outflows from typical star-forming galaxies can eject metals into the CGM and the intergalactic medium (IGM) at z=5-6. Deep, dedicated surveys have searched for Ly$\alpha$ emission associated with strong CIV absorbers at $z\approx 6$, but only a few Ly$\alpha$ emitter candidates have been detected. Interpreting these detections is moreover ambiguous because Ly$\alpha$ is a resonant line, raising the need for complementary techniques for detecting absorbers' host galaxies. Here, using Atacama Large Millimeter Array (ALMA), we report a [C II] 158$\mu$m emitter associated with a strong low-ionization absorber, OI, at $z=5.978$. The projected impact parameter between OI and [C II] emitter is 20.0 kpc. The measured [C II] luminosity is $7.0\times 10^7$ solar luminosities. Further analysis indicates that strong OI absorbers may reside in the circumgalactic medium of massive halos one to two orders of magnitude more massive than expected values.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Mingyu Li
Zheng Cai
Fuyan Bian
Xiaojing Lin
Zihao Li
Yunjing Wu
Fengwu Sun
Shiwu Zhang
Siwei Zou
Xiaohui Fan
Eiichi Egami
Stephane Charlot
Gustavo Bruzual
Jacopo Chevallard
摘要： We present the mass-metallicity relation (MZR) at $z=2-3$ in the stellar mass range of $M_\star\approx 10^{6.5}-10^{9.5}M_\odot$ using 55 dwarf galaxies in the Abell 2744 and SMACS J0723-3732 galaxy cluster fields. These dwarf galaxies are identified and confirmed by deep JWST/NIRISS imaging and slitless grism spectroscopic observations. Taking advantage of the gravitational lensing effect, we extend the previous MZR relation at $z=2-3$ to a much lower mass regime by more than 2.5 orders of magnitude compared with previous studies. We find that the MZR has a shallower slope at the low-mass end ($M_\star10^{9}M_\odot$), with a slope turnover point at around the stellar mass of $10^9 M_\odot$. This implies that dominating feedback processes in dwarf galaxies may be different from that in galaxies with higher mass. From $z=3$ to $z=2$, the metallicity of the dwarf galaxies is enhanced by $\approx0.1$ dex for a given stellar mass, consistent with the mild evolution found in galaxies with higher mass. Further, we confirm the existence of a 3D relation between the gas-phase metallicity, stellar mass, and star formation rate, i.e., fundamental metallicity relation (FMR), in dwarf galaxies at $z=2-3$. Our derived FMR, which has no significant redshift evolution, can be used as a benchmark to understand the origin of the anti-correlation between SFR and metallicity of dwarf galaxies in the high-redshift Universe.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Yunjing Wu
Zheng Cai
Fengwu Sun
Fuyan Bian
Xiaojing Lin
Zihao Li
Mingyu Li
Franz E. Bauer
Eiichi Egami
Xiaohui Fan
Jorge González-López
Jianan Li
Feige Wang
Jinyi Yang
Shiwu Zhang
Siwei Zou
摘要： Spiral arms serve crucial purposes in star formation and galaxy evolution. In this paper, we report the identification of A2744-DSG-$z3$, a dusty, multiarm spiral galaxy at $z=3.059$ using the James Webb Space Telescope (JWST) NIRISS imaging and grism spectroscopy. A2744-DSG-$z3$ was discovered as a gravitationally lensed sub-millimeter galaxy with ALMA. This is the most distant stellar spiral structure seen thus far, consistent with cosmological simulations which suggest $z\approx3$ as the epoch when spirals emerge. Thanks to the gravitational lensing and excellent spatial resolution of JWST, the spiral arms are resolved with a spatial resolution of $\approx290$\,pc. Based on SED fitting, the spiral galaxy has a de-lensed star formation rate of $85\pm30 \ M_{\odot}$ yr$^{-1}$, and a stellar mass of $\approx10^{10.6}M_{\odot}$, indicating that A2744-DSG-$z3$ is a main-sequence galaxy. After fitting the spiral arms, we find a stellar effective radius ($R_{e, \rm{star}}$) of $5.0\pm1.5$ kpc. Combing with ALMA measurements, we find that the effective radii ratio between dust and stars is $\approx0.4$, similar to {those} of massive SFGs at $z\sim2$, indicating a compact dusty core in A2744-DSG-$z3$. Moreover, this galaxy appears to be living in a group environment: including A2744-DSG-$z3$, at least three galaxies at $z=3.05 - 3.06$ {are} spectroscopically confirmed by JWST/NIRISS and ALMA, residing within a lensing-corrected projected scale of $\approx 70$ kpc. This, along with the asymmetric brightness profile, further suggests that the spiral arms may be triggered by minor merger events at $z\gtrsim3$.
分类： 天文学 >> 天文学 提交时间： 2023-02-19
Mingyu Li
Zheng Cai
Fuyan Bian
Xiaojing Lin
Zihao Li
Yunjing Wu
Fengwu Sun
Shiwu Zhang
Siwei Zou
Xiaohui Fan
Eiichi Egami
Stephane Charlot
Gustavo Bruzual
Jacopo Chevallard
摘要： We present the mass-metallicity relation (MZR) at $z=2-3$ in the stellar mass range of $M_\star\approx 10^{6.5}-10^{9.5}M_\odot$ using 55 dwarf galaxies in the Abell 2744 and SMACS J0723-3732 galaxy cluster fields. These dwarf galaxies are identified and confirmed by deep JWST/NIRISS imaging and slitless grism spectroscopic observations. Taking advantage of the gravitational lensing effect, we extend the previous MZR relation at $z=2-3$ to a much lower mass regime by more than 2.5 orders of magnitude compared with previous studies. We find that the MZR has a shallower slope at the low-mass end ($M_\star10^{9}M_\odot$), with a slope turnover point at around the stellar mass of $10^9 M_\odot$. This implies that dominating feedback processes in dwarf galaxies may be different from that in galaxies with higher mass. From $z=3$ to $z=2$, the metallicity of the dwarf galaxies is enhanced by $\approx0.1$ dex for a given stellar mass, consistent with the mild evolution found in galaxies with higher mass. Further, we confirm the existence of a 3D relation between the gas-phase metallicity, stellar mass, and star formation rate, i.e., fundamental metallicity relation (FMR), in dwarf galaxies at $z=2-3$. Our derived FMR, which has no significant redshift evolution, can be used as a benchmark to understand the origin of the anti-correlation between SFR and metallicity of dwarf galaxies in the high-redshift Universe.
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