A Hard X-Ray Test of HCN Enhancements As a Tracer of Embedded Black Hole Growth

Privon, George C.; Ricci, Cláudio; Aalto, S.; Viti, S.; Armus, L.; Díaz-Santos, T.; González-Alfonso, E.; Iwasawa, K.; Jeff, D.; Treister, Ezequiel; Bauer, F. E.; Evans, A. S.; Garg, Prerak; Herrero-Illana, R.; Mazzarella, J. M.; Larson, Kirsten L.; Blecha, Laura; Barcos-Muñoz, Loreto; Charmandaris, V.; Stierwalt, Sabrina; Pérez-Torres, M. A.

doi:10.3847/1538-4357/ab8015

Cited by 70 publications

(51 citation statements)

References 75 publications

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“…This was done including, besides the 23 sources presented here, the 30 objects reported in Ricci et al (2017b), and several sources reported in recent literature (e.g. Iwasawa et al 2020;Privon et al 2020;Yamada et al 2020). Using X-ray spectroscopy, we identify a total of 35 AGNs in these systems, 5 of which are associated with U/LIRGs in the N stage (i.e.…”

Section: X-ray Agnmentioning

confidence: 99%

A hard X-ray view of luminous and ultra-luminous infrared galaxies in GOALS – I. AGN obscuration along the merger sequence

Ricci

Privon

Pfeifle

et al. 2021

Monthly Notices of the Royal Astronomical Society

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The merger of two or more galaxies can enhance the inflow of material from galactic scales into the close environments of Active Galactic Nuclei (AGN), obscuring and feeding the supermassive black hole (SMBH). Both recent simulations and observations of AGN in mergers have confirmed that mergers are related to strong nuclear obscuration. However, it is still unclear how AGN obscuration evolves in the last phases of the merger process. We study a sample of 60 Luminous and Ultra-luminous IR galaxies (U/LIRGs) from the GOALS sample observed by NuSTAR. We find that the fraction of AGN that are Compton-thick (CT; $N_{\rm H}\ge 10^{24}\rm \, cm^{-2}$) peaks at $74_{-19}^{+14}\%$ at a late merger stage, prior to coalescence, when the nuclei have projected separations of dsep ∼ 0.4 − 6 kpc. A similar peak is also observed in the median NH [$(1.6\pm 0.5)\times 10^{24}\rm \, cm^{-2}$]. The vast majority ($85^{+7}_{-9}\%$) of the AGN in the final merger stages (dsep ≲ 10 kpc) are heavily obscured ($N_{\rm H}\ge 10^{23}\rm \, cm^{-2}$), and the median NH of the accreting SMBHs in our sample is systematically higher than that of local hard X-ray selected AGN, regardless of the merger stage. This implies that these objects have very obscured nuclear environments, with the $N_{\rm H}\ge 10^{23}\rm \, cm^{-2}$ gas almost completely covering the AGN in late mergers. CT AGN tend to have systematically higher absorption-corrected X-ray luminosities than less obscured sources. This could either be due to an evolutionary effect, with more obscured sources accreting more rapidly because they have more gas available in their surroundings, or to a selection bias. The latter scenario would imply that we are still missing a large fraction of heavily obscured, lower luminosity ($L_{2-10}\lesssim 10^{43}\rm \, erg\, s^{-1}$) AGN in U/LIRGs.

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Section: X-ray Agnmentioning

confidence: 99%

A hard X-ray view of luminous and ultra-luminous infrared galaxies in GOALS – I. AGN obscuration along the merger sequence

Ricci

Privon

Pfeifle

et al. 2021

Monthly Notices of the Royal Astronomical Society

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“…Table 2 Correlation Coefficients between the Photoelectric Efficiency, as Defined by the Ratio of IR Cooling Lines to Mid-IR PAH Emission between 6 and 17 μm, and Other Quantities in GOALS Star-forming Galaxies Notes. Kendall's τ correlation coefficients (τ k ) and p-values were calculated using pymccorrelation (Privon et al 2020), which implements bootstrap error estimation on τ k and p with censored data (upper limits) as described in Curran (2014) and Isobe et al (1986) respectively. We report 16%, 50%, and 84% percentiles for each quantity.…”

Section: Dust Grain Properties and The Photoelectric Efficiencymentioning

confidence: 99%

Regulating Star Formation in Nearby Dusty Galaxies: Low Photoelectric Efficiencies in the Most Compact Systems

McKinney

Armus

Pope

et al. 2021

ApJ

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Star formation in galaxies is regulated by heating and cooling in the interstellar medium (ISM). In particular, the processing of molecular gas into stars will depend strongly on the ratio of gas heating to gas cooling in the neutral gas around sites of recent star formation. In this work, we combine mid-infrared (mid-IR) observations of polycyclic aromatic hydrocarbons (PAHs), the dominant heating mechanism of gas in the ISM, with [C II], [O I], and [Si II] fine-structure emission, the strongest cooling channels in dense, neutral gas. The ratio of IR cooling line emission to PAH emission measures the photoelectric efficiency, a property of the ISM which dictates how much energy carried by ultraviolet photons gets transferred into the gas. We find that star-forming, IR-luminous galaxies in the Great Observatories All-Sky LIRG Survey with high IR surface densities have low photoelectric efficiencies. These systems also have, on average, higher ratios of radiation field strength to gas densities, and larger average dust grain size distributions. The data support a scenario in which the most compact galaxies have more young starforming regions per unit area that exhibit less efficient gas heating. These conditions may be more common at high z, and may help explain the higher star formation rates at cosmic noon. We make predictions on how this can be investigated with the James Webb Space Telescope.

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“…In this case we turn to the method of Isobe et al (1986) for computing the Kendall tau correlation coefficient with censored data in both axes. We use the implementation of pymccorrelation (Privon et al 2020), which in turn perturbs the data in Monte Carlo fash- ion to compute the errors in the correlation coefficient (Curran 2014).…”

Section: Regressionsmentioning

confidence: 99%

“…Software: COSQUEST (Rupke 2021a), IFSFIT (Rupke 2014;Rupke & Veilleux 2015; Rupke 2021b), LINMIX_ERR (Kelly 2007), pymccorrelation (Privon et al 2020), scipy (Virtanen et al 2020), DRTOOLS (Rupke 2021c)…”

Section: Acknowledgmentsunclassified

Galactic Winds across the Gas-Rich Merger Sequence: I. Highly Ionized N V and O VI Outflows in the QUEST Quasars

Veilleux,

Rupke,

Liu

et al. 2021

Preprint

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This program is part of QUEST (Quasar/ULIRG Evolutionary Study) and seeks to examine the gaseous environments of z 0.3 quasars and ULIRGs as a function of host galaxy properties and age across the merger sequence from ULIRGs to quasars. This first paper in the series focuses on 33 quasars from the QUEST sample and on the kinematics of the highly ionized gas phase traced by the N V λλ1238,1243 and O VI λλ1032,1038 absorption lines in high-quality Hubble Space Telescope (HST) Cosmic Origins Spectrograph (COS) data. N V and O VI outflows are present in about 60% of the QUEST quasars and span a broad range of properties, both in terms of equivalent widths (from 20 mÅ to 25 Å) and kinematics (outflow velocities from a few × 100 km s −1 up to ∼10,000 km s −1 ). The rate of incidence and equivalent widths of the highly ionized outflows are higher among X-ray weak or absorbed sources. The weighted outflow velocity dispersions are highest among the X-ray weakest sources. No significant trends are found between the weighted outflow velocities and the properties of the quasars and host galaxies although this may be due to the limited dynamic range of properties of the current sample. These results will be re-examined in an upcoming paper where the sample is expanded to include the QUEST ULIRGs. Finally, a lower limit of ∼0.1% on the ratio of timeaveraged kinetic power to bolometric luminosity is estimated in the 2−4 objects with blueshifted P V λλ1117,1128 absorption features.

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A Hard X-Ray Test of HCN Enhancements As a Tracer of Embedded Black Hole Growth

Cited by 70 publications

References 75 publications

A hard X-ray view of luminous and ultra-luminous infrared galaxies in GOALS – I. AGN obscuration along the merger sequence

A hard X-ray view of luminous and ultra-luminous infrared galaxies in GOALS – I. AGN obscuration along the merger sequence

Regulating Star Formation in Nearby Dusty Galaxies: Low Photoelectric Efficiencies in the Most Compact Systems

Galactic Winds across the Gas-Rich Merger Sequence: I. Highly Ionized N V and O VI Outflows in the QUEST Quasars

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