A5053592523- Galaxies: Formation, Evolution, Phenomena
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Stellar, planetary, and galactic studies
- Astrophysical Phenomena and Observations
- Gamma-ray bursts and supernovae
- Astronomical Observations and Instrumentation
- Anomaly Detection Techniques and Applications
- Astrophysics and Cosmic Phenomena
- Geochemistry and Geologic Mapping
- Advanced X-ray and CT Imaging
- Radioactive Decay and Measurement Techniques
- Neural Networks and Applications
- Computational Physics and Python Applications
- Scientific Computing and Data Management
- Research Data Management Practices
- Plant Water Relations and Carbon Dynamics
- Multidisciplinary Science and Engineering Research
- High-pressure geophysics and materials
- Evolutionary Algorithms and Applications
- Semiconductor Lasers and Optical Devices
- Radio Astronomy Observations and Technology
- Spectroscopy and Laser Applications
- Seismic Waves and Analysis
- Solar and Space Plasma Dynamics
Carnegie Observatories
2023-2024
Carnegie Institution for Science
2023-2024
Tel Aviv University
2014-2021
Astronomy is experiencing a rapid growth in data size and complexity. This change fosters the development of data-driven science as useful companion to common model-driven analysis paradigm, where astronomers develop automatic tools mine datasets extract novel information from them. In recent years, machine learning algorithms have become increasingly popular among astronomers, are now used for wide variety tasks. light these developments, promise challenges associated with them, IAC Winter...
We report on the determination of electron densities, and their impact outflow masses rates, measured in central few hundred parsecs 11 local luminous active galaxies. show that peak integrated line emission AGN is significantly offset from systemic velocity as traced by stellar absorption features, indicating profiles are dominated outflow. In contrast, matched inactive galaxies characterised a weaker wing. present three independent estimates density these AGN, discussing merits different...
How can we discover objects did not know existed within the large datasets that now abound in astronomy? We present an outlier detection algorithm developed, based on unsupervised Random Forest. test more than two million galaxy spectra from Sloan Digital Sky Survey and examine 400 galaxies with highest score. find which have extreme emission line ratios abnormally strong absorption lines, unusual continua, including extremely reddened galaxies. galaxy-galaxy gravitational lenses,...
The global influence of AGN-driven outflows remains uncertain, due to a lack large samples with accurately-determined outflow properties. In the second paper this series, we determine mass and energetics ionized is 234 type II AGN, largest such sample date, by combining infrared emission dust in wind (paper I) line We provide new general expressions for properties outflowing gas, which depend on ionization state gas. also present novel method estimate electron density outflow, based optical...
Abstract The structure and chemistry of the dusty interstellar medium (ISM) are shaped by complex processes that depend on local radiation field, gas composition, dust grain properties. Of particular importance polycyclic aromatic hydrocarbons (PAHs), which emit strong vibrational bands in mid-infrared, play a key role ISM energy balance. We recently identified global correlations between PAH band optical line ratios across three nearby galaxies, suggesting connection heating ionization...
Abstract We present a comparison of observed polycyclic aromatic hydrocarbon (PAH) feature ratios in 19 nearby galaxies with grid theoretical expectations for near- and mid-infrared dust emission. The PAH are drawn from Cycle 1 JWST observations measured 7224 stellar clusters 29,176 associations which we have robust ages mass estimates Hubble Space Telescope five-band photometry. Though there galaxy-to-galaxy variations, the largely agree models, particularly those that skewed toward more...
Abstract Combining Atacama Large Millimeter/submillimeter Array CO(2–1) mapping and JWST near- mid-infrared imaging, we characterize the relationship between polycyclic aromatic hydrocarbon (PAH) emission at ≈100 pc resolution in 70 nearby star-forming galaxies. Leveraging a new Cycle 2 Treasury program targeting galaxies, expand sample size by more than an order of magnitude compared to previous CO–PAH comparisons. In regions galaxies where most gas is likely be molecular, find strong...
ABSTRACT We report on our combined analysis of HST, VLT/MUSE, VLT/SINFONI, and ALMA observations the local Seyfert 2 galaxy, NGC 5728 to investigate in detail feeding feedback active galactic nucleus (AGN). The data sets simultaneously probe morphology, excitation, kinematics stars, ionized gas, molecular gas over a large range spatial scales (10 pc 10 kpc). contains stellar bar that is driving along prominent dust lanes inner 1 kpc where settles into circumnuclear ring. ring strongly star...
Post starburst E+A galaxies show indications of a powerful that was quenched abruptly. Their disturbed, bulge-dominated morphologies suggest they are merger remnants. The more massive suggested to be by AGN feedback, yet little is known about AGN-driven winds in this short-lived phase. We present spatially-resolved IFU spectroscopy the Keck Cosmic Web Imager SDSS J003443.68+251020.9, at z=0.118. system consists two galaxies, larger which post galaxy hosting an AGN. Our modelling suggests 400...
Abstract The PHANGS survey uses Atacama Large Millimeter/submillimeter Array, Hubble Space Telescope, Very and JWST to obtain an unprecedented high-resolution view of nearby galaxies, covering millions spatially independent regions. high dimensionality such a diverse multiwavelength data set makes it challenging identify new trends, particularly when they connect observables from different wavelengths. Here, we use unsupervised machine-learning algorithms mine this information-rich novel...
In this work we apply and expand on a recently introduced outlier detection algorithm that is based an unsupervised random forest. We use the to calculate similarity measure for stellar spectra from Apache Point Observatory Galactic Evolution Experiment (APOGEE). show traces non-trivial physical properties contains information about complex structures in data. it visualization clustering of dataset, discuss its ability find groups highly similar objects, including spectroscopic twins. Using...
Abstract The scaling relations between supermassive black holes and their host galaxy properties are of fundamental importance in the context hole-host co-evolution throughout cosmic time. In this work, we use a novel algorithm that identifies smooth trends complex data sets apply it to sample 2000 type 1 active galactic nuclei (AGNs) spectra. We detect sequence emission line shapes strengths which reveals correlation narrow L([O iii])/L(H β) ratio width broad H α. This relation ties...
Abstract Machine learning (ML) algorithms have become increasingly important in the analysis of astronomical data. However, because most ML are not designed to take data uncertainties into account, ML-based studies mostly restricted with high signal-to-noise ratios. Astronomical sets such quality uncommon. In this work, we modify long-established Random Forest (RF) algorithm account measurements (i.e., features) as well assigned classes labels). To do so, Probabilistic (PRF) treats features...
ABSTRACT E+A galaxies are believed to be a short phase connecting major merger ultraluminous infrared (ULIRGs) with red and dead elliptical galaxies. Their optical spectrum suggests massive starburst that was quenched abruptly, their bulge-dominated morphologies tidal tails suggest they remnants. Active galactic nucleus (AGN)-driven winds one of the processes responsible for sudden quenching star formation expulsion and/or destruction remaining molecular gas. Little is known about AGN-driven...
ABSTRACT Post-starburst galaxies are believed to be in a rapid transition between major merger starbursts and quiescent ellipticals. Their optical spectrum is dominated by A-type stars, suggesting starburst that was quenched recently. While observations suggest little ongoing star formation, some have been shown host significant molecular gas reservoirs. This led the suggestion depletion not required end starburst, formation suppressed other processes. We present NOEMA CO(1−0) of 15...
We present a comparison of observed polycyclic aromatic hydrocarbon (PAH) feature ratios in 19 nearby galaxies with grid theoretical expectations for near- and mid-infrared dust emission. The PAH are drawn from Cycle 1 JWST observations measured 7224 stellar clusters 29176 associations which we have robust ages mass estimates HST five-band photometry. Though there galaxy-to-galaxy variations, the largely agree models, particularly those that skewed toward more ionized larger size...
Radiation pressure is a key mechanism by which stellar feedback disrupts molecular clouds and drives HII region expansion. This includes direct radiation exerted UV photons on dust grains, associated with photoionization, infrared (IR) grains due to dust-reprocessed IR photons. We present new method that combines high resolution mid-IR luminosities from JWST-MIRI, optical attenuation nebular line measurements VLT-MUSE, HST H$\alpha$-based sizes estimate the strength of in $\approx 18,000$...
Abstract JWST observations, when combined with Hubble Space Telescope (HST) data, promise to improve age estimates of star clusters in nearby spiral galaxies. However, feedback from young cluster stars pushes out the natal gas and dust, making formation evolution a challenge model. Here, we use JWST+ HST observations galaxy NGC 628 produce spectral energy distribution (SED) templates compact spanning 275 nm through 21 μ m. These preliminary SEDs capture associated dust within radii ≈0...
Abstract Radiation pressure is a key mechanism by which stellar feedback disrupts molecular clouds and drives H ii region expansion. This includes direct radiation exerted UV photons on dust grains, associated with photoionization, infrared (IR) grains due to dust-reprocessed IR photons. We present new method that combines high-resolution mid-IR luminosities from JWST-MIRI, optical attenuation, nebular line measurements the Very Large Telecope Multi-Unit Spectroscopic Explorer (VLT-MUSE),...
Using over a million and half extragalactic spectra we study the properties of mysterious Diffuse Interstellar Bands (DIBs) in Milky Way. These data provide us with an unprecedented sampling skies at high Galactic-latitude low dust-column-density. We present our method, correlation equivalent width 8 DIBs dust extinction few atomic species, distribution four - 5780.6A, 5797.1A, 6204.3A, 6613.6A nearly 15000 squared degrees. As previously found, strengths correlate therefore inevitably each...
Post starburst E+A galaxies are thought to have experienced a significant that was quenched abruptly. Their disturbed, bulge-dominated morphologies suggest they merger remnants. We present ESI/Keck observations of SDSS J132401.63+454620.6, post galaxy at redshift z = 0.125, with started 400 Myr ago, and other properties, like star formation rate (SFR) consistent what is measured in ultra luminous infrared (ULRIGs). The shows both zero velocity narrow lines, blueshifted broader Balmer...
Large scale outflows of different gas phases are ubiquitous in the host galaxies active galactic nuclei (AGN). Despite their many differences, they share a common property - all contain dust. The dust is carried with outflow, heated by AGN, and emits at infrared wavelengths. This paper shows that emission this can be used to detect AGN derive properties. We use sample about 4000 type II compare properties systems show spectroscopic signature ionized do not. an additional mid-infrared...
ABSTRACT Post-starburst E+A galaxies are systems that hosted a powerful starburst was quenched abruptly. Simulations suggest these provide the missing link between major merger ULIRGs and red dead ellipticals, where AGN feedback is responsible for expulsion or destruction of molecular gas. However, many details remain unresolved little known about AGN-driven winds in this short-lived phase. We present spatially resolved IFU spectroscopy with MUSE/VLT SDSS J124754.95-033738.6, post-starburst...
We present a statistical analysis of the optical properties an X-ray selected Type 1 AGN sample, using high signal to-noise ratio ($S/N>20$) spectra counterparts ROSAT/2RXS sources in footprint SDSS-IV/SPIDERS (Spectroscopic IDentification eROSITA Sources) programme. The final sample contains 2100 sources. It significantly extends redshift and luminosity ranges ($\rm z \sim 0.01 - 0.80$ $\rm L_{0.1-2.4 \,keV}$ ~ 2.0 \times 10^{41}$ 1.0 10^{46} \, erg s^{-1}$ ) used so far this kind analysis....
ABSTRACT The typical optical–UV continuum slopes observed in many type-1 active galactic nuclei (AGNs) are redder than expected from thin accretion disk (AD) models. A possible resolution to this conundrum is that AGNs reddened by dust along the line of sight. To explore possibility, we stack 5000 SDSS with luminosity <?CDATA $L\approx {10}^{45}\,\mathrm{erg}\,{{\rm{s}}}^{-1}$?> and redshift $z\sim 0.4$?> bins optical slope ${\alpha }_{\mathrm{opt}}$?> width broad H β emission line. We...