Related papers: Revealing Ionization Conditions of Sz 102 with Spa…
High-energy radiation from T Tauri stars (TTS) influences the amount and longevity of gas in disks, thereby playing a crucial role in the creation of gas giant planets. Here we probe the high-energy ionizing radiation from TTS using…
The results of photometric, polarimetric and spectroscopic observations of the young star ZZ Tau IRS in the visible and near-infrared bands are presented. Against the continuum of an M spectral type star about 50 emission lines of allowed…
Galaxies in the reionization-era have been shown to have prominent [OIII]+H$\beta$ emission. Little is known about the gas conditions and radiation field of this population, making it challenging to interpret the spectra emerging at…
Most of the observed emission lines and continuum excess from young accreting low mass stars (Classical T Tauri stars -- CTTSs) take place in the star-disk or inner disk region. These regions have a complex emission topology still largely…
We use near-IR grism spectroscopy from the Hubble Space Telescope to examine the strength of [Ne~III] 3869 relative to H-beta, [O~II] 3727 and [O~III] 5007 in 236 low mass (7.5 < log (Mstar/Msolar) < 10.5) star-forming galaxies in the…
Understanding when and how circumstellar disks disperse is crucial to constrain planet formation and migration. Thermal winds powered by high-energy stellar photons have long been theorized to drive disk dispersal. However, evidence for…
We present VLT-SINFONI near infra-red spectra of 26 new heavily reddened quasar candidates selected from the UKIDSS-LAS, VISTA VHS and VIKING imaging surveys. This new sample extends our reddened quasar search to both brighter and fainter…
Using spatially-resolved spectra obtained with the Low Resolution Imaging Spectrometer at the Keck I telescope, we investigate the nature of ionizing sources and kinematic properties of emission-line gas in a LINER galaxy SDSS…
We present deep spectroscopy of 17 very low mass (M* ~ 2.0x10^6 Msun to 1.4x10^9 Msun) and low luminosity (M_UV ~ -13.7 to -19.9) gravitationally lensed galaxies in the redshift range z~1.5-3.0. Deep rest-frame ultraviolet spectra reveal…
We present new observations of near-infrared molecular hydrogen (H2) line emission in a sample of 18 Class I and flat-spectrum low mass protostars, primarily in the Tau- Aur and {\rho} Oph dark clouds. The line emission is extended by up to…
In accreting young stars one of the prominent spectral features in the near infrared is the Paschen and Brackett series in emission. We examine hydrogen line ratios for 16 classical T Tauri stars from SpeX spectra and and assess the trends…
Accretion and ejection sets the outcome of the star and planet formation process. The mid-infrared wavelength range offers key tracers of those processes that were difficult to detect and spatially resolve in protostars until now. We aim to…
As the James Webb Space Telescope approaches scientific operation, there is much interest in exploring the redshift range beyond that accessible with Hubble Space Telescope imaging. Currently, the only means to gauge the presence of such…
We investigate spatially-resolved emission-line ratios in a sample of 219 galaxies ($0.6<z<1.3$) detected using the G102 grism on the \emph{Hubble Space Telescope} Wide Field Camera 3, taken as part of the CANDELS Ly$\alpha$ Emission at…
Very little information has been so far gathered on atomic jets from young embedded low mass sources (class I stars), especially in the inner jet region. We exploit multiwave spectroscopic observations to infer physical conditions of the…
We present an analysis of the gas physics at the base of jets from five T Tauri stars based on high angular resolution optical spectra, using the Hubble Space Telescope Imaging Spectrograph (HST/STIS). The spectra refer to a region within…
We have undertaken a program to observe emission lines of SIV 10.5, NeII 12.8, NeIII 15.6, & SIII 18.7 um in a number of extragalactic HII regions with the Spitzer Space Telescope. We report our results for the nearly face-on spiral galaxy…
We analyzed high-resolution mid-infrared spectra of 78 well-known Herbig Ae/Be (HAeBe) stars using Spitzer InfraRed Spectrograph data, focusing on the detection of [Ne {\sc II}] and [Ne {\sc III}] emission lines as indicators of ionized…
[Ne II] 12.81 $\mu\mathrm{m}$ emission is a well-used tracer of protoplanetary disk winds due to its blueshifted line profile. MIRI-MRS recently observed T Cha, detecting this line along with lines of [Ne III], [Ar II] and [Ar III], with…
We report the first detection of variability in the mid-infrared neon line emission of a protoplanetary disk by comparing a JWST MIRI MRS spectrum of SZ Cha taken in 2023 with a Spitzer IRS SH spectrum of this object from 2008. We measure…