Elena Manjavacas
A5007400170- Stellar, planetary, and galactic studies
- Astronomy and Astrophysical Research
- Astrophysics and Star Formation Studies
- Astro and Planetary Science
- Adaptive optics and wavefront sensing
- Astronomical Observations and Instrumentation
- Gamma-ray bursts and supernovae
- Spectroscopy and Laser Applications
- CCD and CMOS Imaging Sensors
- Geophysics and Gravity Measurements
- Calibration and Measurement Techniques
- History and Developments in Astronomy
- Atmospheric and Environmental Gas Dynamics
- Spacecraft Design and Technology
- Satellite Communication Systems
- Astrophysical Phenomena and Observations
- Solar and Space Plasma Dynamics
- Satellite Image Processing and Photogrammetry
- Atmospheric Ozone and Climate
- Astronomical and nuclear sciences
- Optical Wireless Communication Technologies
- Algorithms and Data Compression
- Space Science and Extraterrestrial Life
- Atmospheric aerosols and clouds
- Particle Accelerators and Free-Electron Lasers
Johns Hopkins University
2022-2024
Space Telescope Science Institute
2022-2024
Association of Universities For Research In Astronomy
2023
University of Baltimore
2023
W.M. Keck Observatory
2019-2021
University of Arizona
2017-2020
Max Planck Institute for Astronomy
2014-2019
Max Planck Society
2013-2019
Instituto de Astrofísica de Canarias
2015-2017
Universidad de La Laguna
2017
We provide an overview of the design and capabilities near-infrared spectrograph (NIRSpec) onboard James Webb Space Telescope. NIRSpec is designed to be capable carrying out low-resolution ($R\!=30\!-330$) prism spectroscopy over wavelength range $0.6-5.3\!~\mu$m higher resolution ($R\!=500\!-1340$ or $R\!=1320\!-3600$) grating $0.7-5.2\!~\mu$m, both in single-object mode employing any one five fixed slits, a 3.1$\times$3.2 arcsec$^2$ integral field unit, multiobject novel programmable...
We provide an overview of the capabilities and performance Near-Infrared Spectrograph (NIRSpec) on James Webb Space Telescope (JWST) when used in its multi-object spectroscopy (MOS) mode employing a novel Micro Shutter Array (MSA) slit device. The MSA consists four separate 98 arcsec $\times$ 91 quadrants each containing $365\times171$ individually addressable shutters whose open areas sky measure 0.20 0.46 0.27 0.53 pitch. This is first time that configurable spectrograph has been available...
The Near-Infrared Spectrograph (NIRSpec) on the James Webb Space Telescope (JWST) offers first opportunity to use integral-field spectroscopy from space at near-infrared wavelengths. More specifically, NIRSpec's unit can obtain spectra covering wavelength range $0.6 - 5.3~\mu$m for a contiguous 3.1 arcsec $\times$ 3.2 sky area spectral resolutions of $R \approx 100$, 1000, and 2700. In this paper we describe optical mechanical design NIRSpec mode, together with its expected performance. We...
Abstract The Near-Infrared Spectrograph (NIRSpec) is one of the four focal plane instruments on James Webb Space Telescope. In this paper, we summarize in-orbit performance NIRSpec, as derived from data collected during its commissioning campaign and first few months nominal science operations. More specifically, discuss some critical hardware components such two NIRSpec Hawaii-2RG detectors, wheel mechanisms, microshutter array. We also accuracy target acquisition procedures used to...
Observations of transiting gas giant exoplanets have revealed a pervasive depletion methane, which has only recently been identified atmospherically. The is thought to be maintained by disequilibrium processes such as photochemistry or mixing from hotter interior. However, the interiors are largely unconstrained along with vertical strength and upper limits on CH$_4$ available. warm Neptune WASP-107 b stands out among an unusually low density, reported core mass, temperatures amenable though...
The Near-Inrared Spectrograph (NIRSpec) on the James Webb Space Telescope (JWST) is a very versatile instrument, offering multiobject and integral field spectroscopy with varying spectral resolution ($\sim$30 to $\sim$3000) over wide wavelength range from 0.6 5.3 micron, enabling scientists study many science themes ranging first galaxies bodies in our own Solar System. In addition its unit support for spectroscopy, NIRSpec features several fixed slits aperture specifically designed enable...
Abstract We report on James Webb Space Telescope (JWST) commissioning observations of the transiting exoplanet HAT-P-14 b, obtained using Bright Object Time Series (BOTS) mode NIRSpec instrument with G395H/F290LP grating/filter combination (3–5 μ m). While data were used primarily to verify that BOTS is working as expected, and enable it for general scientific use, they yield a precise transmission spectrum which we find featureless down precision level instrument, consistent expectations...
Abstract The unprecedented medium-resolution ( R λ ∼ 1500–3500) near- and mid-infrared (1–18 μ m) spectrum provided by JWST for the young (140 ± 20 Myr) low-mass (12–20 M Jup ) L–T transition (L7) companion VHS 1256 b gives access to a catalog of molecular absorptions. In this study, we present comprehensive analysis data set utilizing forward-modeling approach applying our Bayesian framework, ForMoSA . We explore five distinct atmospheric models assess their performance in estimating key...
Abstract Spectra of young benchmark brown dwarfs with well-known ages are vital to characterize other dwarfs, for which in general not known. These spectra also crucial test atmospheric models, have the potential provide detailed information about atmospheres these objects. However, models optimally, medium-resolution, long-wavelength-coverage well-understood uncertainties ideal, such as provided by NIRSpec instrument on board James Webb Space Telescope. In this paper, we present...
We present simultaneous 0.65-2.5 microns medium resolution (3300 < R 8100) VLT/X-Shooter spectra of the young low-mass (19+/-5MJup) L-T transition object VHS 1256-1257 b, a known spectroscopic analogue HR8799d. The companion is prime target for JWST Early Release Science (ERS) and one highest-amplitude variable brown-dwarf to date. compare spectrum custom grids cloudless ATMO models exploring different atmospheric composition with Bayesian inference tool ForMoSA. also re-analyze...
We report the results of a $J$-band survey for photometric variability in sample young, low-gravity objects using New Technology Telescope (NTT) and United Kingdom InfraRed (UKIRT). Surface gravity is key parameter atmospheric properties brown dwarfs this first large that aims to test dependence properties. do full analysis spectral signatures youth assess group membership probability each target tools from literature. This 30 object young dwarfs. Since we are lacking with types later than...
We present 1-5um spectroscopy of the young planetary mass companion TWA 27B (2M1207B) performed with NIRSpec on board James Webb Space Telescope. In these data, fundamental band CH_4 is absent and CO weak. The nondetection reinforces a previously observed trend weaker younger ages among L dwarfs, which has been attributed to enhanced non-equilibrium chemistry objects. weakness may reflect an additional atmospheric property that varies age, such as temperature gradient or cloud thickness. are...
Abstract We present a performance analysis for the aperture masking interferometry (AMI) mode on board James Webb Space Telescope Near Infrared Imager and Slitless Spectrograph (JWST/NIRISS). Thanks to self-calibrating observables, AMI accesses inner working angles down even within classical diffraction limit. The scientific potential of this has recently been demonstrated by Early Release Science (ERS) 1386 program with deep search close-in companions in HIP 65426 exoplanetary system. As...
Detecting atmospheres around planets with a radius below 1.6 R$_{\oplus}$, commonly referred to as rocky (Rogers_2015, Rogers_2021), has proven be challenging. However, orbiting M-dwarfs are ideal candidates due their favorable planet-to-star ratio. Here, we present one transit observation of the Super-Earth L98-59d (1.58 2.31 M$_{\oplus}$), at limit rocky/gas-rich, using JWST NIRSpec G395H mode covering 2.8 5.1 microns wavelength range. The extracted spectrum from single deviates flat line...
Context. Accurate parallax measurements allow us to determine physical properties of brown dwarfs and help constrain evolutionary atmospheric models, break age-mass degeneracy, reveal unresolved binaries.
We obtained medium-resolution near-infrared spectra of seven young M9.5-L3 dwarfs classified in the optical. aim to confirm low surface gravity objects NIR. also test whether atmospheric models correctly represent formation and settling dust clouds atmosphere late-M L dwarfs. used ISAAC at VLT obtain targets. compared them those mature BD, late-type companions nearby stars with known ages, order identify study gravity-sensitive features. computed spectral indices weakly sensitive derive...
As part of our ongoing NTT SoFI survey for variability in young free-floating planets and low-mass brown dwarfs, we detect significant the young, planetary-mass object PSO J318.5–22, likely due to rotational modulation inhomogeneous cloud cover. A member 23 ± 3 Myr β Pic moving group, J318.5–22 has Teff = K a mass estimate 8.3 0.5 MJup age. is intermediate between 51 Eri b b, two known exoplanet companions group. With amplitudes from 7% 10% JS at separate epochs over 3–5 hr observations,...
Abstract Bayesian atmospheric retrieval tools can place constraints on the properties of brown dwarfs' and hot Jupiters' atmospheres. To fully exploit these methods, high signal-to-noise spectral libraries with well-understood uncertainties are essential. We present a library (1.10–1.69 μ m) thermal emission 76 dwarfs Jupiters. All our spectra have been acquired Hubble Space Telescope ’s Wide Field Camera 3 instrument its G141 grism. The near-infrared types objects range from L4 to Y1. Eight...
Abstract We present 1–5 μ m spectroscopy of the coldest known brown dwarf, WISE J085510.83−071442.5 (WISE 0855), performed with Near-Infrared Spectrograph (NIRSpec) on board James Webb Space Telescope (JWST). NIRSpec has dramatically improved measurement spectral energy distribution (SED) 0855 in terms wavelength coverage, signal-to-noise ratios, and resolution. have preliminary modeling data using ATMO 2020 models cloudless atmospheres, arriving at a best-fitting model that T eff = 285 K....
We report results from 8 hours of JWST/MIRI LRS spectroscopic monitoring directly followed by 7 JWST/NIRSpec prism the benchmark binary brown dwarf WISE 1049AB, closest, brightest dwarfs known. find water, methane, and CO absorption features in both components, including 3.3 $\mu$m methane feature a tentative detection small grain ($<$ 1$\mu$m) silicate at $>$8.5 1049A. Both components vary significantly ($>$1$\%$), with 1049B displaying larger variations than Using K-means clustering, we...
Observations of rotational modulations brown dwarfs and giant exoplanets allow the characterization condensate cloud properties. As now spectral have only been seen in three L-type dwarfs. We report here discovery LP261-75B, an L6-type intermediate surface gravity companion to M4.5 star. a part Cloud Atlas Treasury program we acquired time-resolved Wide Field Camera 3 grism spectroscopy (1.1--1.69~$\mu$m) LP261-75B. find gray variations with relative amplitude displaying weak wavelength...
Abstract We present simultaneous Hubble Space Telescope ( HST) WFC3+ Spitzer IRAC variability monitoring for the highly variable young (∼20 Myr) planetary-mass object PSO J318.5−22. Our HST + observations covered approximately two rotation periods with and most of a period . derive 8.6 ± 0.1 hr from light curve. Combining this measured <?CDATA $v\sin i$?> object, we find an inclination 56.°2 8.°1. measure peak-to-trough amplitudes 3.4% 0.1% Channel 2 4.4%–5.8% (typical 68% confidence errors...
Measurements of photometric variability at different wavelengths provide insights into the vertical cloud structure brown dwarfs and planetary-mass objects. In seven Hubble Space Telescope consecutive orbits, spanning $\sim$10 h observing time}, we obtained time-resolved spectroscopy T8-dwarf Ross 458C using near-infrared Wide Field Camera 3. We found spectrophotometric with a peak-to-peak signal 2.62$\pm$0.02 % (in 1.10-1.60~$\mu$m white light curve). Using three methods, estimated...
Excess infrared flux from white dwarf stars is likely to arise a dusty debris disk or cool companion. In this work, we present near-infrared spectroscopic observations with Keck/MOSFIRE, Gemini/GNIRS, and Gemini/Flamingos-2 of seven dwarfs excesses identified in previous studies. We confirmed the presence dust disks around four (Gaia J0611-6931, Gaia J0006+2858, J2100+2122, WD 0145+234) as well two new brown pairs J0052+4505 J0603+4518). three systems, detected for first time metal emissions...
Abstract Directly imaged planetary-mass companions offer unique opportunities in atmospheric studies of exoplanets. They share characteristics both brown dwarfs and transiting exoplanets, therefore are critical for connecting characterizations these objects. Rotational phase mapping is a powerful technique to constrain the condensate cloud properties ultra-cool atmospheres. Applying this directly will be extremely valuable constraining models low mass surface-gravity atmospheres determining...