A5028060062- Astronomy and Astrophysical Research
- Galaxies: Formation, Evolution, Phenomena
- Stellar, planetary, and galactic studies
- Astronomical Observations and Instrumentation
- Astrophysical Phenomena and Observations
- Calibration and Measurement Techniques
- Dark Matter and Cosmic Phenomena
- Pulsars and Gravitational Waves Research
- Astrophysics and Star Formation Studies
- Adaptive optics and wavefront sensing
- Scientific Research and Discoveries
- Gamma-ray bursts and supernovae
- Geophysics and Gravity Measurements
- Phase Equilibria and Thermodynamics
- Astrophysics and Cosmic Phenomena
- Remote Sensing in Agriculture
- Atmospheric Ozone and Climate
- Spectroscopy and Chemometric Analyses
- CCD and CMOS Imaging Sensors
- Statistical and numerical algorithms
Royal Observatory
2024-2025
University of Edinburgh
2024-2025
University College London
2022-2024
Netherlands Institute for Radio Astronomy
2024
University of Manchester
2020
We present a comparative study of the low-frequency eclipses spider (compact, irradiating binary) PSRs B1957+20 and J1816+4510. Combining these data with those three other eclipsing systems we frequency dependence eclipse duration. J1816+4510 have similar orbital properties, but companions to pulsars masses that differ by an order magnitude. A dedicated campaign simultaneously observe pulsed imaged continuum flux densities throughout reveals many similarities between excess material within...
Abstract Extremely metal-poor galaxies (XMPGs) at relatively low redshift are excellent laboratories for studying galaxy formation and evolution in the early universe. Much effort has been spent on identifying them from large-scale spectroscopic surveys or follow-up observations. Previous work identified a few hundred XMPGs. In this work, we obtain large sample of 223 XMPGs z < 1 data Dark Energy Spectroscopic Instrument (DESI). The oxygen abundance is determined using direct T e method...
We present an analysis of the rest-frame optical ($\lambda \simeq 3100-5600 \,$\r{A}) spectrum a $\mathrm{log}_{10}(M_*/\mathrm{M_\odot}) = 8.6$ star-forming galaxy at $z=8.271$ (EXCELS-63107) from JWST/NIRSpec medium-resolution observations taken as part EXCELS survey. EXCELS-63107 is compact object consistent with size local cluster complexes ($r_e < 200 \, \rm{pc}$) and has extremely steep UV continuum measured JWST/NIRCam photometry ($\beta=-3.3\pm0.3$). The G395M notable for its strong...
We present an analysis of the rest-frame optical spectra 22 [OIII]$\lambda$4363 detected galaxies in redshift range $1.65 < z 7.92$ (with $\langle \rangle$ = 4.05) from JWST/NIRSpec medium-resolution observations taken as part EXCELS survey. To supplement these high-redshift sources, we also consider a sample 782 local DESI Early Data Release. Our demonstrates that many strong-line calibrations are biased early Universe due to systematic evolution ionization conditions with redshift....
ABSTRACT We present determinations of the gas-phase and stellar metallicities a sample 65 star-forming galaxies at $z \simeq 3.5$ using rest-frame far-ultraviolet (FUV) spectroscopy from VANDELS survey in combination with follow-up optical VLT/KMOS Keck/MOSFIRE. infer oxygen abundances ($Z_{\mathrm{g}}$; tracing O/H) via strong nebular lines iron ($Z_{\star }$; Fe/H) full spectral fitting to FUV continuum. Our spans mass range $8.5 \lt \mathrm{log}(M_{\star }/\mathrm{M}_{\odot }) 10.5$ shows...
Abstract We present an analysis of eight star-forming galaxies with 〈z〉 = 4.0 from the JWST EXCELS survey for which we obtain robust chemical abundance estimates α-elements O, Ne and Ar. The are primarily produced via core-collapse supernovae (CCSNe) should result in α-element ratios that do not vary significantly across cosmic time. However, Type Ia (SNe Ia) models predict excess production Ar relative to O Ne. Ar/O ratio can therefore be used as a tracer enrichment CCSNe SNe galaxies. Our...
Aims. We present an extensive catalog of the physical properties more than a million galaxies investigated with Dark Energy Spectroscopic Instrument (DESI), one largest spectroscopic surveys to date. Spanning full range target types, including emission-line galaxies, luminous red and quasars, our survey encompasses unprecedented redshifts, all way from 0 6. Methods. The properties, such as stellar masses star formation rates, were derived via CIGALE spectral energy distribution (SED) fitting...
ABSTRACT The gas-phase metallicity of galaxies encodes important information about galaxy evolution processes, in particular star formation, feedback, outflows, and gas accretion, the relative importance which can be extracted from systematic trends scatter mass–metallicity relation (MZR). Here, we use a sample low-redshift (0.02 &lt; z 0.055) SDSS to investigate nature around MZR, observables physical processes causing it, its dependence on mass. We cold masses inferred optical emission...
Gas plays an important role in many processes galaxy formation and evolution, but quantifying the importance of gas has been hindered by challenge to measure masses for large samples galaxies. Datasets direct atomic molecular measurements are sufficient establish simple scaling relations, often not enough quantify three-parameter or second order dependencies. As alternative approach, we derive here indirect cold from optical emission lines using photoionization models galaxies SDSS main...
We present a spectroscopic analysis of two star-forming galaxies at z~5 observed with JWST/NIRSpec as part the Early eXtragalactic Continuum and Emission Line Science (EXCELS) survey. The detection C III]$\lambda\lambda$1906,09, [O II]$\lambda\lambda$3726,29, III]$\lambda\lambda$4363,5007, [N II]$\lambda$6584 nebular emission lines enables investigation C/O, N/O, C/N abundance ratios using temperature-sensitive method. have stellar masses log($M_{\star}$/M$_{\odot}$ ) = 8.13$\pm$0.09...
Extremely metal-poor galaxies (XMPGs) at relatively low redshift are excellent laboratories for studying galaxy formation and evolution in the early universe. Much effort has been spent on identifying them from large-scale spectroscopic surveys or follow-up observations. Previous work identified a few hundred XMPGs. In this work, we obtain large sample of 223 XMPGs $z<1$ data Dark Energy Spectroscopic Instrument (DESI). The oxygen abundance is determined using direct $T_{\rm e}$ method based...
We present determinations of the gas-phase and stellar metallicities a sample 65 star-forming galaxies at $z \simeq 3.5$ using rest-frame far-ultraviolet (FUV) spectroscopy from VANDELS survey in combination with follow-up optical VLT/KMOS Keck/MOSFIRE. infer oxygen abundances ($Z_{\mathrm{g}}$; tracing O/H) via strong nebular lines iron ($Z_{\star}$; Fe/H) full spectral fitting to FUV continuum. Our spans mass range $8.5 < \mathrm{log}(M_{\star}/\mathrm{M}_{\odot}) 10.5$ shows clear...
Aims. We present an extensive catalog of the physical properties more than a million galaxies within Dark Energy Spectroscopic Instrument (DESI), one largest spectroscopic surveys to date. Spanning over full variety target types, including emission line and luminous red as well quasars, our survey encompasses unprecedented range redshifts, stretching from 0 6. Methods. The properties, such stellar masses star formation rates, are derived via CIGALE spectral energy distribution (SED) fitting...
Galaxy scaling relations provide insights into the processes that drive galaxy evolution. The extension of these dwarf regime is particular interest. This because galaxies represent a crucial stage in evolution, and understanding them could also shed light on their role reionising early Universe. There currently no consensus dominate evolution dwarfs. In this work we constrain atomic gas sequence (stellar mass vs. fraction) mass-metallicity relation phase metallicity) from ($10^{6.5}$...
ABSTRACT Galaxy scaling relations provide insights into the processes that drive galaxy evolution. The extension of these dwarf regime is particular interest. This because galaxies represent a crucial stage in evolution, and understanding them could also shed light on their role reionizing early Universe. There currently no consensus dominate evolution dwarfs. In this work, we constrain atomic gas sequence (stellar mass versus fraction) mass–metallicity relation gas-phase metallicity) from...
We present an analysis of nine star-forming galaxies with $\langle z \rangle = 3.95$ from the JWST EXCELS survey for which we obtain robust chemical abundance estimates $\alpha$-elements O, Ne and Ar. The are primarily produced via core-collapse supernovae (CCSNe) should result in $\alpha$-element ratios that do not vary significantly across cosmic time. However, Type Ia (SNe Ia) models predict excess production Ar relative to O Ne. Ar/O ratio can therefore be used as a tracer enrichment...
The gas-phase metallicity of galaxies encodes important information about galaxy evolution processes, in particular star formation, feedback, outflows and gas accretion, the relative importance which can be extracted from systematic trends scatter mass-metallicity relation (MZR). Here, we use a sample low redshift (0.02 < z 0.055) SDSS to investigate nature around MZR, observables physical processes causing it, its dependence on mass. We cold masses inferred optical emission lines using...