Dust and Cold Gas Properties of Starburst HyLIRG-Quasars at $z \sim 2.5$

Fuente: arXiv
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Autori principali: Liu, Feng-Yuan, Dai, Y. Sophia, Omont, Alain, Liu, Daizhong, Cox, Pierre, Neri, Roberto, Krips, Melanie, Yang, Chentao, Wu, Xue-Bing, Huang, Jia-Sheng
Natura: Preprint
Pubblicazione: 2024
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author Liu, Feng-Yuan
Dai, Y. Sophia
Omont, Alain
Liu, Daizhong
Cox, Pierre
Neri, Roberto
Krips, Melanie
Yang, Chentao
Wu, Xue-Bing
Huang, Jia-Sheng
author_facet Liu, Feng-Yuan
Dai, Y. Sophia
Omont, Alain
Liu, Daizhong
Cox, Pierre
Neri, Roberto
Krips, Melanie
Yang, Chentao
Wu, Xue-Bing
Huang, Jia-Sheng
contents Some high-z active galactic nuclei (AGNs) are found to reside in extreme star-forming galaxies, such as hyper-luminous infrared galaxies (HyLIRGs), with AGN-removed $L_{\rm{IR}}$ of $>10^{13} L_{\rm{\odot}}$. In this paper, we report NOEMA observations of six apparent starburst HyLIRGs associated with optical quasars at $z\sim2-3$ in the Stripe 82 field, to study their dust and molecular CO properties. Five out of the six candidates are detected with CO(4-3) or CO(5-4) emission, and four in 2mm dust continuum. Based on the linewidth-$L'_{\rm{CO(1-0)}}$ diagnostics, we find that four galaxies are likely unlensed or weakly lensed sources. The molecular gas mass is in the range of $μM_{\rm{H_2}} \sim0.8-9.7\times10^{10} M_{\odot}$ (with $α= 0.8 M_{\odot} (\rm{K km s^{-1} pc^2})^{-1}$ and $μ$ is the unknown possible gravitational magnification factor). We fit their SEDs, after including the observed 2mm fluxes and upper limits, and estimate their apparent (uncorrected for possible lensing effect) star formation rates ($μ$SFRs) to be $\sim400-2500$ $M_{\rm{\odot}} \rm{yr^{-1}}$ with depletion time of $\sim20-110$ Myr. We notice interesting offsets, of $\sim10-40$ kpc spatially or $\sim1000-2000$ km s$^{-1}$ spectroscopically, between the optical quasar and the mm continuum or CO emissions. The observed velocity shift is likely related to the blueshifted broad-emission-line region of quasars, though mergers or recoiling black holes are also possible causes, which can explain the spatial offset and the high intrinsic SFRs in the HyLIRG-quasar systems.
format Preprint
id arxiv_https___arxiv_org_abs_2402_03909
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Dust and Cold Gas Properties of Starburst HyLIRG-Quasars at $z \sim 2.5$
Liu, Feng-Yuan
Dai, Y. Sophia
Omont, Alain
Liu, Daizhong
Cox, Pierre
Neri, Roberto
Krips, Melanie
Yang, Chentao
Wu, Xue-Bing
Huang, Jia-Sheng
Astrophysics of Galaxies
Some high-z active galactic nuclei (AGNs) are found to reside in extreme star-forming galaxies, such as hyper-luminous infrared galaxies (HyLIRGs), with AGN-removed $L_{\rm{IR}}$ of $>10^{13} L_{\rm{\odot}}$. In this paper, we report NOEMA observations of six apparent starburst HyLIRGs associated with optical quasars at $z\sim2-3$ in the Stripe 82 field, to study their dust and molecular CO properties. Five out of the six candidates are detected with CO(4-3) or CO(5-4) emission, and four in 2mm dust continuum. Based on the linewidth-$L'_{\rm{CO(1-0)}}$ diagnostics, we find that four galaxies are likely unlensed or weakly lensed sources. The molecular gas mass is in the range of $μM_{\rm{H_2}} \sim0.8-9.7\times10^{10} M_{\odot}$ (with $α= 0.8 M_{\odot} (\rm{K km s^{-1} pc^2})^{-1}$ and $μ$ is the unknown possible gravitational magnification factor). We fit their SEDs, after including the observed 2mm fluxes and upper limits, and estimate their apparent (uncorrected for possible lensing effect) star formation rates ($μ$SFRs) to be $\sim400-2500$ $M_{\rm{\odot}} \rm{yr^{-1}}$ with depletion time of $\sim20-110$ Myr. We notice interesting offsets, of $\sim10-40$ kpc spatially or $\sim1000-2000$ km s$^{-1}$ spectroscopically, between the optical quasar and the mm continuum or CO emissions. The observed velocity shift is likely related to the blueshifted broad-emission-line region of quasars, though mergers or recoiling black holes are also possible causes, which can explain the spatial offset and the high intrinsic SFRs in the HyLIRG-quasar systems.
title Dust and Cold Gas Properties of Starburst HyLIRG-Quasars at $z \sim 2.5$
topic Astrophysics of Galaxies
url https://arxiv.org/abs/2402.03909