arXiv subjects

Eduardo Gonzalez-Alfonso

Publications and source records attributed to Eduardo Gonzalez-Alfonso.

11 recordsLinked to original sources

arXiv2026

Resolving the Multiphase Outflow, Shock Signatures, and PAHs in the AGN-Starburst Composite ULIRG F10565+2448 with JWST MIRI/MRS

We present new James Webb Space Telescope Mid-Infrared Instrument (MIRI) Medium-Resolution Spectrometer (MRS) observations of the nearby ultra-luminous infrared galaxy F10565+2448. These integral field spectroscopic data reveal an unresolved nuclear outflow in both warm-ionized and warm-molecular gas phases as well as a resolved blueshifted kpc-scale warm-molecular outflow. The unresolved warm-ionized outflow has a mean projected velocity up to $-520$ km/s, while the unresolved warm-molecular outflow is slower at $-150$ km/s. For the resolved warm-molecular outflow, the projected mean velocity ($-280 < v_{50} < -110$ km/s) is only slightly faster than the velocity of the disk ($-70 < v_{50} < 120$ km/s) and as such likely does not exceed the estimated escape velocity of $\gtrsim 300$ km/s. The warm-molecular outflow is slightly hotter ($507 \pm 25$K) than the disk ($329 \pm 5$K), and displays areas of higher temperature and lower column density that may indicate a shock front, which we explore using the [Fe II] 5.34 $μ$m/Pf$α$ shock diagnostic. Analysis of the polycyclic aromatic hydrocarbon features reveal trends of ionization and grain size that first decrease with radius up to 1 kpc before increasing up to 3 kpc. These results bolster the picture of F10565+2448 being an AGN-starburst composite where both star formation and AGN-powered phenomena are required to explain the outflow energetics.

astro-ph.GA↗

arXiv2026

Molecular Outflows in the Nucleus of the Nearby Compton-thick AGN NGC 3079

We present Northern Extended Millimeter Array (NOEMA) observations of the CO (2-1) molecular gas kinematics in the nearby Compton-thick Seyfert 2 galaxy NGC 3079, with an angular resolution of 0.5" ($\sim$40 pc). To interpret the observed CO (2-1) kinematics, we model the rotating disk using two software tools, 3D-Barolo and DysmalPy, to generate mock 3D data cubes. Both models indicate, in addition to the rotating disk, the presence of a spatially unresolved nuclear component characterized by high velocity dispersion. Analysis of the visibility data reveals that the blue-shifted, high-velocity component is spatially offset from the continuum peak by 0.17" ($\sim$ 14 pc) and exhibits line-of-sight velocities of $v$ - $v_{sys}$ = -350 to -450 km s$^{-1}$, which we interpret as a nuclear molecular outflow. We calculate a molecular gas mass outflow rate of 8.82 $M_\odot$ yr$^{-1}$, with a kinetic power ($\dot{E}_{\text{out}}$) of 3.8 $\times$ 10$^{41}$ erg s$^{-1}$ and a momentum rate ($\dot{p}_{\text{out}}$) of 2.05 $\times$ 10$^{34}$ Dyne. The momentum rate exceeds the AGN radiation momentum rate by a factor of $\sim$15, suggesting an energy-driven outflow. Furthermore, we argue that the derived kinetic power of the nuclear molecular outflow favors a jet-powered scenario that explains the slowdown and brightening of the parsec-scale radio source observed with the Very Long Baseline Array.

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arXiv2026

JWST Discovery of High-Velocity Mid-Infrared Ionized Outflows in Ultraluminous Infrared Galaxies F11119+3257 and F05189-2524

Ultra-fast outflows (UFOs) are thought to be a driving mechanism of large-scale winds driven by active galactic nuclei, which cause significant galactic feedback through quenching star formation and regulating supermassive black hole growth. We present James Webb Space Telescope (JWST) Mid-Infrared Instrument Medium-Resolution Spectrometer observations of two nearby ultraluminous infrared galaxies (ULIRGs), F11119+3257 and F05189-2524, with nuclear X-ray detected UFOs and kiloparsec-scale outflow. These galaxies show remarkably similar mid-infrared continuum and emission line features, notably including a high-velocity $v_{90}$ $\sim$ 4000 km s$^{-1}$ outflow detected in highly ionized neon emission lines, e.g., \nevi. In F05189-2524, we see a slightly slower biconical outflow extending up to $\sim2$ kpc in the same neon emission lines. Both sources show evidence of AGN-driven radiative feedback through a deficit of rotational molecular hydrogen lines in the nuclear region, $<$1 kpc from the central quasar, but no clear evidence of any molecular gas entrained in the quasar-driven outflow. Energetic analysis shows that the warm ionized gas in both of these sources contributes minimally ($\sim0.1-5\%$) to the momentum outflow rate of these sources and leaves the conclusions of previous literature unchanged: the energetics of these sources are broadly consistent with a momentum-conserving outflow.

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arXiv2024

JWST Discovery of a Very Fast Biconical Outflow of Warm Molecular Gas in the Nearby Ultra-Luminous Infrared Galaxy F08572+3915 NW

We present new James Webb Space Telescope (JWST) Mid-Infrared Instrument (MIRI) Medium-Resolution Spectrometer (MRS) observations of the nearby ultra-luminous infrared galaxy (ULIRG) F08572+3915 NW. These integral field spectroscopic (IFS) data reveal a kpc-scale warm-molecular rotating disk and biconical outflow traced by the H$_2$ $ν$ = 0$-$0 S(1), S(2), S(3), and S(5) rotational transitions. The outflow maintains a relatively constant median (maximum) projected velocity of 1100 km s$^{-1}$ (3000 km s$^{-1}$) out to $\sim$ 1.4 kpc from the nucleus. The outflowing H$_2$ material is slightly warmer (640 $-$ 700 K) than the rotating disk material (460 $-$ 520 K), perhaps due to shock heating in the highly turbulent outflowing material. This outflow shares the same kinematics and orientation as the sub-kpc scale warm-H$_2$ outflow traced by the ro-vibrational H$_2$ lines in Keck AO near-infrared IFS data. However, this warm-H$_2$ outflow is significantly faster than the sub-kpc scale cold-molecular outflow derived from multi-transition far-infrared OH observations with Herschel and the $\gtrsim$ kpc-scale cold-molecular outflow mapped by mm-wave interferometric CO 1$-$0 observations with IRAM-PdBI and NOEMA. The new JWST data bolster the scenario where the buried quasar in this ULIRG is excavating the dust screen, accelerating perhaps as much as 60\% of the dusty warm-molecular material to velocities beyond the escape velocity, and thus influencing the evolution of the host galaxy.

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arXiv2021

Deeply Buried Nuclei in the Infrared-Luminous Galaxies NGC 4418 and Arp 220: I. ALMA Observations at $λ= $1.4-0.4 mm and Continuum Analysis

We observed with ALMA three deeply buried nuclei in two galaxies, NGC 4418 and Arp 220, at $\sim$0.2$''$ resolution over a total bandwidth of 67 GHz in $f_{\rm rest}$ = 215 - 697 GHz. Here we (1) introduce our program, (2) describe our data reduction method for wide-band, high-resolution imaging spectroscopy, (3) analyze in visibilities the compact nuclei with line forests, (4) develop a continuum-based estimation method of dust opacity and gas column density in heavily obscured nuclei, which uses the BGN (buried galactic nuclei) model and is sensitive to $\log(N_{\rm H_2}/{\rm cm}^{-2}) \sim $ 25 - 26 at $λ\sim 1$ mm, and (5) present the continuum data and diagnosis of our targets. The three continuum nuclei have major-axis FWHM of $\sim$0.1$''$-0.3$''$ (20-140 pc) aligned to their rotating nuclear disks of molecular gas. However, each nucleus is described better with two or three concentric components than with a single Gaussian. The innermost cores have sizes of 0.05$''$-0.10$''$ (8-40 pc), peak brightness temperatures of ~100-500 K at 350 GHz, and more fractional flux at lower frequencies. The intermediate components correspond to the nuclear disks. They have axial ratios of $\approx$0.5 and hence inclinations $\stackrel{>}{\sim} 60$ deg. The outermost elements include the bipolar outflow from Arp 220W. We estimate 1 mm dust opacity of $τ_{\rm d,1mm} \approx 2.2$, $1.2$, and $\stackrel{<}{\sim} 0.4$ respectively for NGC 4418, Arp 220W, and Arp 220E. The first two correspond to $\log(N_{\rm H}/{\rm cm}^{-2}) \sim 26$ for conventional dust-opacity laws, and hence the nuclei are highly Compton thick.

astro-ph.GA↗

arXiv2020

Super Hot Cores in NGC 253: Witnessing the formation and early evolution of Super Star Clusters

Using $0.2^{\prime \prime}$ ($\sim3$ pc) ALMA images of vibrationally excited HC$_3$N emission (HC$_3$N$^*$) we reveal the presence of $8$ unresolved Super Hot Cores (SHCs) in the inner $160$ pc of NGC\,253. Our LTE and non-LTE modelling of the HC$_3$N$^*$ emission indicate that SHCs have dust temperatures of $200-375$ K, relatively high H$_2$ densities of $1-6\times 10^{6}$ cm$^{-3}$ and high IR luminosities of $0.1-1\times 10^8$ L$_\odot$. As expected from their short lived phase ($\sim 10^4$ yr), all SHCs are associated with young Super Star Clusters (SSCs). We use the ratio of luminosities form the SHCs (protostar phase) and from the free-free emission (ZAMS star phase), to establish the evolutionary stage of the SSCs. The youngest SSCs, with the larges ratios, have ages of a few $10^4$ yr (proto-SSCs) and the more evolved SSCs are likely between $10^5$ and $10^6$ yr (ZAMS-SSCs). The different evolutionary stages of the SSCs are also supported by the radiative feedback from the UV radiation as traced by the HNCO/CS ratio, with this ratio being systematically higher in the young proto-SSCs than in the older ZAMS-SSCs. We also estimate the SFR and the SFE of the SSCs. The trend found in the estimated SFE ($\sim40\%$ for proto-SSCs and $>85\%$ for ZAMS-SSCs) and in the gas mass reservoir available for star formation, one order of magnitude higher for proto-SSCs, suggests that star formation is still going on in proto-SSCs. We also find that the most evolved SSCs are located, in projection, closer to the center of the galaxy than the younger proto-SSCs, indicating an inside-out SSC formation scenario.

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arXiv2016

HERUS: A CO Atlas from SPIRE Spectroscopy of local ULIRGs

We present the Herschel SPIRE Fourier Transform Spectroscopy (FTS) atlas for a complete flux limited sample of local Ultra-Luminous Infra-Red Galaxies as part of the HERschel ULIRG Survey (HERUS). The data reduction is described in detail and was optimized for faint FTS sources with particular care being taken with the subtraction of the background which dominates the continuum shape of the spectra. Special treatment in the data reduction has been given to any observation suffering from artefacts in the data caused by anomalous instrumental effects to improve the final spectra. Complete spectra are shown covering $200 - 671μ$m with photometry in the SPIRE bands at 250$μ$m, 350$μ$m and 500$μ$m. The spectra include near complete CO ladders for over half of our sample, as well as fine structure lines from [CI] 370 $μ$m, [CI] 609 $μ$m, and [NII] 205 $μ$m. We also detect H$_{2}$O lines in several objects. We construct CO Spectral Line Energy Distributions (SLEDs) for the sample, and compare their slopes with the far-infrared colours and luminosities. We show that the CO SLEDs of ULIRGs can be broadly grouped into three classes based on their excitation. We find that the mid-J (5$<$J$<$8) lines are better correlated with the total far-infrared luminosity, suggesting that the warm gas component is closely linked to recent star-formation. The higher J transitions do not linearly correlate with the far-infrared luminosity, consistent with them originating in hotter, denser gas unconnected to the current star-formation. {\bf We conclude that in most cases more than one temperature components are required to model the CO SLEDs.}

astro-ph.GA↗

arXiv2013

Far-infrared Fine-Structure Line Diagnostics of Ultraluminous Infrared Galaxies

We present Herschel observations of six fine-structure lines in 25 Ultraluminous Infrared Galaxies at z<0.27. The lines, [O III]52, [N III]57, [O I]63, [N II]122, [O I]145, and [C II]158, are mostly single gaussians with widths <600 km s-1 and luminosities of 10^7 - 10^9 Solar. There are deficits in the [O I]63/L_IR, [N II]/L_IR, [O I]145/L_IR, and [C II]/L_IR ratios compared to lower luminosity systems. The majority of the line deficits are consistent with dustier H II regions, but part of the [C II] deficit may arise from an additional mechanism, plausibly charged dust grains. This is consistent with some of the [C II] originating from PDRs or the ISM. We derive relations between far-IR line luminosities and both IR luminosity and star formation rate. We find that [N II] and both [O I] lines are good tracers of IR luminosity and star formation rate. In contrast, [C II] is a poor tracer of IR luminosity and star formation rate, and does not improve as a tracer of either quantity if the [C II] deficit is accounted for. The continuum luminosity densities also correlate with IR luminosity and star formation rate. We derive ranges for the gas density and ultraviolet radiation intensity of 10^1 < n < 10^2.5 and 10^2.2 < G_0 < 10^3.6, respectively. These ranges depend on optical type, the importance of star formation, and merger stage. We do not find relationships between far-IR line properties and several other parameters; AGN activity, merger stage, mid-IR excitation, and SMBH mass. We conclude that these far-IR lines arise from gas heated by starlight, and that they are not strongly influenced by AGN activity.

astro-ph.CO↗

arXiv2007

Spitzer-IRS high resolution spectroscopy of the 12μm Seyfert galaxies: I. First results

The first high resolution Spitzer IRS 9-37um spectra of 29 Seyfert galaxies (about one quarter) of the 12um Active Galaxy Sample are presented and discussed. The high resolution spectroscopy was obtained with corresponding off-source observations. This allows excellent background subtraction, so that the continuum levels and strengths of weak emission lines are accurately measured. The result is several new combinations of emission line ratios, line/continuum and continuum/continuum ratios that turn out to be effective diagnostics of the strength of the AGN component in the IR emission of these galaxies. The line ratios [NeV]/[NeII], [OIV]/[NeII], already known, but also [NeIII]/[NeII] and [NeV]/[SiII] can all be effectively used to measure the dominance of the AGN. We extend the analysis, already done using the 6.2um PAH emission feature, to the equivalent width of the 11.25um PAH feature, which also anti-correlates with the dominance of the AGN. We measure that the 11.25um PAH feature has a constant ratio with the H_2 S(1) irrespective of Seyfert type, approximately 10 to 1. Using the ratio of accurate flux measurements at about 19um with the two spectrometer channels, having aperture areas differing by a factor 4, we measured the source extendness and correlated it with the emission line and PAH feature equivalent widths. The extendness of the source gives another measure of the AGN dominance and correlates both with the EWs of [NeII] and PAH emission. Using the rotational transitions of H$_2$ we were able to estimate temperatures (200-300K) and masses (1-10 x 10^6 M_sun), or significant limits on them, for the warm molecular component in the galaxies observed.

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arXiv2005

The far-infrared emission line and continuum spectrum of the Seyfert galaxy NGC 1068

The first complete far-infrared spectrum (43-197um) of the Seyfert 2 galaxy NGC 1068 as observed with the LWS onboard ISO is reported. In addition to the expected ionic fine structure emission lines, the OH rotational lines at 79, 119 and 163um were all detected in emission. The line intensities were modelled together with ISO SWS and optical and UV line intensities from the literature, considering two independent emission components: the AGN component and the starburst component in the circumnuclear ring of 3 kpc in size. Using the UV to mid-IR emission line spectrum to constrain the nuclear ionizing continuum, we have confirmed previous results: a canonical power-law ionizing spectrum is a poorer fit than one with a deep absorption trough, while the presence of a big blue bump is ruled out. Based on starburst synthesis models, we were able to fit the mid- and far-infrared fine-structure line emission, with a low ionization parameter (logU=-3.5) and low densities (n=100 cm^-3). Combining AGN and starburst components, we succeeded in modeling the overall UV to far-IR atomic spectrum of NGC1068, reproducing the line fluxes to within a factor 2.0 on average with a standard deviation of 1.3 and the overall continuum as the sum of the contribution of the thermal dust emission in the ionized and neutral components. TheOH 119 um emission indicates that the line is collisionally excited and arises in a warm and dense region. The OH emission has been modeled using spherically symmetric, non-local, non-LTE radiative transfer models. The models indicate that the bulk of the emission arises from the nuclear region, although some extended contribution from the starburst is not ruled out. The OH abundance in the nuclear region is expected to be $\sim10^{-5}$, characteristic of X-ray dominated regions.

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arXiv1999

Extended Far-Infrared CO Emission in the Orion OMC-1 Core

We report on sensitive far-infrared observations of $^{12}$CO pure rotational transitions in the OMC-1 core of Orion. The lines were observed with the Long Wavelength Spectrometer (LWS) in the grating mode on board the Infrared Space Observatory (ISO), covering the 43-197 $μ$m wavelength range. The transitions from $J_{up}=14$ up to $J_{up}=19$ have been identified across the whole OMC-1 core and lines up to $J_{up}= 43$ have been detected towards the central region, KL/IRc2. In addition, we have taken high-quality spectra in the Fabry-Perot mode of some of the CO lines. In KL/IRc2 the lines are satisfactorily accounted for by a three-temperature model describing the plateau and ridge emission. The fluxes detected in the high-$J$ transitions ($J_{up} > 34$) reveal the presence of a very hot and dense gas component ($T=1500-2500$ K; $\rm N(CO)$=2\times 10^{17}\cmmd$), probably originating from some of the embedded sources previously observed in the $\rm H_2$ near-infrared lines. At all other positions in the OMC-1 core, we estimate kinetic temperatures $\geq 80$ K and as high as 150 K at some positions around IRc2, from a simple Large-Velocity Gradient model.

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