The Circumnuclear Environment of IRAS 20551-4250: A Case Study of AGN/Starburst Connection for<i>JWST</i>

Sani, E.; Nardini, E.

doi:10.1155/2012/783451

Cited by 5 publications

(1 citation statement)

References 36 publications

(78 reference statements)

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“…Much evidence points to this system being at the end of the ULIRG phase: a regular velocity field in the disk, centrally concentrated Hα, and the fact that population synthesis modelling (Johansson 1991) suggests that the peak in star formation already occurred some 10 7 yr ago. Point-like hard X-ray sources have been detected with both XMM-Newton (Franceschini et al 2003) and Chandra (Ptak et al 2003), and those, together with more analyses of Spitzer /IRS spectroscopy suggest that this system hosts a highly obscured AGN (Farrah et al 2007;Sani & Nardini 2012), again consistent with the evolved nature of this ULIRG. In our Hα maps, we find evidence for fast-flowing gas that is highly suggestive of a turbulent outflow.…”

Section: Iras 20551-4250mentioning

confidence: 72%

Spatially resolved observations of warm ionized gas and feedback in local ULIRGs★

Westmoquette

Clements

Bendo

et al. 2012

Monthly Notices of the Royal Astronomical Society

102

129

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We present Very Large Telescope (VLT)/VIsible MultiObject Spectrograph integral field unit (VIMOS‐IFU) emission‐line spectroscopy of a volume‐limited sample of 18 southern ultraluminous infrared galaxies (ULIRGs) selected with z < 0.09 and δ < 10. By covering a wide range of ULIRG types, including many systems that have received very little previous attention, this data set provides an important set of templates for comparison with high‐redshift galaxies. We employed an automated Gaussian line‐fitting programme to decompose the emission‐line profiles of Hα, [N ii], [S ii] and [O i] into individual components, and chart the Hα kinematics, and the ionized gas excitations and densities. 11 out of 18 of our galaxies show evidence for outflowing warm ionized gas with speeds between 500 and a few 1000 km s−1, with the fastest outflows associated with systems that contain an active galactic nucleus. Our spatially resolved spectroscopy has allowed us to map the outflows, and in some cases determine for the first time to which nucleus the wind is associated. In three of our targets we find line components with widths >2000 km s−1 over spatially extended regions in both the recombination and forbidden lines; in two of these three, they are associated with a known Sy2 nucleus. Eight galaxies have clear rotating gaseous discs, and for these we measure rotation velocities, virial masses, and calculate Toomre Q parameters. We find radial gradients in the emission‐line ratios in a significant number of systems in our study. We attribute these gradients to changes in ionizing radiation field strength, most likely due to an increasing contribution of shocks with radius. We conclude with a detailed discussion of the results for each individual system, with reference to the existing literature. Our observations demonstrate that the complexity of the kinematics and gas properties in ULIRGs can only be disentangled with high sensitivity, spatially resolved IFU observations. Many of our targets are ideal candidates for future high spatial resolution follow‐up observations.

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Section: Iras 20551-4250mentioning

confidence: 72%

Spatially resolved observations of warm ionized gas and feedback in local ULIRGs★

Westmoquette

Clements

Bendo

et al. 2012

Monthly Notices of the Royal Astronomical Society

102

129

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High resolution ALMA observations of dense molecular medium in the central regions of active galaxies

et al. 2015

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Abstract. In the central regions of active galaxies, dense molecular medium are exposed to various types of radiation and energy injections, such as UV, X-ray, cosmic ray, and shock dissipation. With the rapid progress of chemical models and implementation of new-generation mm/submm interferometry, we are now able to use molecules as powerful diagnostics of the physical and chemical processes in galaxies. Here we give a brief overview on the recent ALMA results to demonstrate how molecules can reveal underlying physical and chemical processes in galaxies. First, new detections of Galactic molecular absorption systems with elevated HCO/H 13 CO + column density ratios are reported, indicating that these molecular media are irradiated by intense UV fields. Second, we discuss the spatial distributions of various types of shock tracers including HNCO, CH3OH and SiO in NGC 253 and NGC 1068. Lastly, we provide an overview of proposed diagnostic methods of nuclear energy sources using ALMA, with an emphasis on the synergy with sensitive mid-infrared spectroscopy, which will be implemented by JWST and SPICA to disentangle the complex nature of heavily obscured galaxies across the cosmic time.

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A NEW INFRARED COLOR CRITERION FOR THE SELECTION OF 0 <z< 7 AGNs: APPLICATION TO DEEP FIELDS AND IMPLICATIONS FORJWSTSURVEYS

Messias

Afonso

Salvato

et al. 2012

ApJ

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It is widely accepted that observations at mid-infrared (mid-IR) wavelengths enable the selection of galaxies with nuclear activity, which may not be revealed even in the deepest X-ray surveys. Many mid-IR color-color criteria have been explored to accomplish this goal and tested thoroughly in the literature. Besides missing many low-luminosity active galactic nuclei (AGN), one of the main conclusions is that, with increasing redshift, the contamination by non-active galaxies becomes significant (especially at z 2.5). This is problematic for the study of the AGN phenomenon in the early Universe, the main goal of many of the current and future deep extra-galactic surveys. In this work new near-and mid-IR color diagnostics are explored, aiming for improved efficiency -better completeness and less contamination -in selecting AGN out to very high redshifts. We restrict our study to the James Webb Space Telescope wavelength range (0.6-27 µm). The criteria are created based on the predictions by state-of-the-art galaxy and AGN templates covering a wide variety of galaxy properties, and tested against control samples with deep multi-wavelength coverage (ranging from the X-rays to radio frequencies). We show that the colors K s − [4.5], [4.5] − [8.0], and [8.0] − [24]are ideal as AGN/non-AGN diagnostics at, respectively, z 1, 1 z 2.5, and z 2.5 − 3. However, when the source redshift is unknown, these colors should be combined. We thus develop an improved IR criterion (using K and IRAC bands, KI) as a new alternative at z 2.5. KI does not show improved completeness (50-60% overall) in comparison to commonly used IRAC-based AGN criteria, but is less affected by non-AGN contamination (revealing a >50-90% level of successful AGN selection). We also propose KIM (using K, IRAC, and MIPS-24 µm bands, KIM), which aims to select AGN hosts from local distances to as far back as the end of reionization (0 < z 7) with reduced non-AGN contamination. However, the necessary testing-constraints and the small control-sample sizes prevent the confirmation of its improved efficiency at z 2.5. Overall, KIM shows a ∼30-40% completeness and a >70-90% level of successful AGN selection. KI and KIM are built to be reliable against a ∼10-20% error in flux, are based on existing filters, and are suitable for immediate use.

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The Circumnuclear Environment of IRAS 20551-4250: A Case Study of AGN/Starburst Connection forJWST

Cited by 5 publications

References 36 publications

Spatially resolved observations of warm ionized gas and feedback in local ULIRGs★

Spatially resolved observations of warm ionized gas and feedback in local ULIRGs★

High resolution ALMA observations of dense molecular medium in the central regions of active galaxies

A NEW INFRARED COLOR CRITERION FOR THE SELECTION OF 0 <z< 7 AGNs: APPLICATION TO DEEP FIELDS AND IMPLICATIONS FORJWSTSURVEYS

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