ORCID Profile
0000-0003-3577-3540
Current Organisation
The University of Texas at Austin
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Publisher: American Astronomical Society
Date: 04-2021
Abstract: The projected stellar rotational velocity ( ) is critical for our understanding of processes related to the evolution of angular momentum in pre-main-sequence stars. We present measurements of high-resolution infrared and optical spectroscopy for 70 pre-main-sequence stars in the Taurus–Auriga star-forming region, in addition to effective temperatures measured from line-depth ratios, as well as stellar rotation periods determined from optical photometry. From the literature, we identified the stars in our s le that show evidence of residing in circumstellar disks or multiple systems. The comparison of infrared measurements calculated using two techniques shows a residual scatter of ∼1.8 km s −1 , defining a typical error floor for the of pre-main-sequence stars from infrared spectra. A comparison of the distributions of stars with and without companions shows that binaries/multiples typically have a higher measured , which may be caused by contamination by companion lines, shorter disk lifetimes in binary systems, or tidal interactions in hierarchical triples. A comparison of optical and infrared values shows no significant difference regardless of whether the star has a disk or not, indicating that CO contamination from the disk does not impact measurements above the typical ∼1.8 km s −1 error floor of our measurements. Finally, we observe a lack of a correlation between the , presence of a disk, and H-R diagram position, which indicates a complex interplay between stellar rotation and evolution of pre-main-sequence stars.
Publisher: SPIE
Date: 06-08-2014
DOI: 10.1117/12.2055487
Publisher: SPIE
Date: 09-08-2016
DOI: 10.1117/12.2232809
Publisher: American Astronomical Society
Date: 18-08-2016
Publisher: American Astronomical Society
Date: 08-2023
Abstract: We present a s le of four emission-line galaxies at z = 6.11–6.35 that were serendipitously discovered using the commissioning data for the James Webb Space Telescope (JWST)/NIRCam wide-field slitless spectroscopy mode. One of them (at z = 6.11) has been reported previously, while the others are new discoveries. These sources are selected by the secure detections of both [O iii ] λ 5007 and H α lines with other fainter lines, which were tentatively detected in some cases (e.g., [O ii ] λ 3727, [O iii ] λ 4959). In the [O iii ]/H β –[N ii ]/H α Baldwin–Phillips–Terlevich diagram, these galaxies occupy the same parameter space as that of z ∼ 2 star-forming galaxies, indicating that they have been enriched rapidly to subsolar metallicities (∼0.4 Z ⊙ ), similar to galaxies with comparable stellar masses at much lower redshifts. The detection of strong H α lines suggests a higher ionizing photon production efficiency within galaxies in the early universe. We find brightening of the [O iii ] λ 5007 line-luminosity function (LF) from z = 3 to 6, and weak or no redshift evolution of the H α line LF from z = 2 to 6. Both LFs are underpredicted at z ∼ 6 by a factor of ∼10 in certain cosmological simulations. This further indicates a global Ly α photon escape fraction of 7%–10% at z ∼ 6, which is slightly lower than previous estimates through the comparison of the UV-derived star formation rate density and Ly α luminosity density. Our s le recovers 66 − 44 + 128 % of z = 6.0–6.6 galaxies in the survey volume with stellar masses greater than 5 × 10 8 M ⊙ , suggesting the ubiquity of strong H α and [O iii ] line emitters in the Epoch of Reionization, which will be further uncovered in the era of JWST.
Publisher: SPIE
Date: 24-09-2012
DOI: 10.1117/12.925402
Publisher: SPIE
Date: 29-08-2022
DOI: 10.1117/12.2628986
No related grants have been discovered for Daniel Jaffe.