RECORD
A Spectroscopic Search for Leaking Lyman Continuum at z~0.7
Cosmology and Nongalactic Astrophysics · Submitted 30 Jul 2010
abstract compiled · 2026-09-23 · no language-model review
The authors' main claim The contrast between these z~0.7 low escape fraction LBG analogs with z~3 LBGs suggests that either the processes conducive to high escape fractions are not being selected for in the z<1 samples or the average escape fraction is decreasing from z~3 to z~1.
The compiled record
The paper's own sentences, arranged. Each label is drawn from a closed vocabulary; the number beside it is the probability the classifier gave that label. Numbers in the tables are the authors', checked by code. No sentence in this record was written by a model.
Open the compiled record
The abstract, sentence by sentence
We present the results of rest-frame, UV slitless spectroscopic observations of a sample of 32 z~0.7 Lyman break galaxy (LBG) analogs in the COSMOS field. The spectroscopic search was performed with the Solar Blind Channel (SBC) on Hubble Space Telescope. We report the detection of leaking Lyman continuum (LyC) radiation from an AGN-starburst composite. While we find no direct detections of LyC emission in the remainder of our sample, we achieve individual lower limits (3 sigma) of the observed non-ionizing UV to LyC flux density ratios, f_{nu}(1500A)/f_{nu}(830A) of 20 to 204 (median of 73.5) and 378.7 for the stack. Assuming an intrinsic Lyman break of 3.4 and an intergalactic medium (IGM) transmission of LyC photons along the line of sight to the galaxy of 85% we report an upper limit for the relative escape fraction in individual galaxies of 0.02 - 0.19 and a stacked 3 sigma upper limit of 0.01. We find no indication of a relative escape fraction near unity as seen in some LBGs at z~3. Our UV spectra achieve the deepest limits to date at any redshift for the escape fraction in individual sources. The contrast between these z~0.7 low escape fraction LBG analogs with z~3 LBGs suggests that either the processes conducive to high escape fractions are not being selected for in the z<1 samples or the average escape fraction is decreasing from z~3 to z~1. We discuss possible mechanisms which could affect the escape of LyC photons.
background contribution method result interpretation main claim
| # | sentence | role | the authors' own work | states the main conclusion | strength |
|---|---|---|---|---|---|
| s0 | We present the results of rest-frame, UV slitless spectroscopic observations of a sample of 32 z~0.7 Lyman break galaxy (LBG) analogs in the COSMOS field. | contribution 0.87 | 0.96 | 0.03 | asserted 0.97 |
| s1 | The spectroscopic search was performed with the Solar Blind Channel (SBC) on Hubble Space Telescope. | method 1.00 | 0.88 | 0.02 | asserted 1.00 |
| s2 | We report the detection of leaking Lyman continuum (LyC) radiation from an AGN-starburst composite. | result 1.00 | 0.96 | 0.55 | asserted 1.00 |
| s3 | While we find no direct detections of LyC emission in the remainder of our sample, we achieve individual lower limits (3 sigma) of the observed non-ionizing UV to LyC flux density ratios, f_{nu}(1500A)/f_{nu}(830A) of 20 to 204 (median of 73.5) and 378.7 for the stack. | result 1.00 | 0.97 | 0.13 | asserted 1.00 |
| s4 | Assuming an intrinsic Lyman break of 3.4 and an intergalactic medium (IGM) transmission of LyC photons along the line of sight to the galaxy of 85% we report an upper limit for the relative escape fraction in individual galaxies of 0.02 - 0.19 and a stacked 3 sigma upper limit of 0.01. | result 1.00 | 0.95 | 0.21 | asserted 0.99 |
| s5 | We find no indication of a relative escape fraction near unity as seen in some LBGs at z~3. | result 0.89 | 0.94 | 0.31 | asserted 0.99 |
| s6 | Our UV spectra achieve the deepest limits to date at any redshift for the escape fraction in individual sources. | result 0.51 | 0.95 | 0.14 | asserted 1.00 |
| s7 | The contrast between these z~0.7 low escape fraction LBG analogs with z~3 LBGs suggests that either the processes conducive to high escape fractions are not being selected for in the z<1 samples or the average escape fraction is decreasing from z~3 to z~1. | interpretation 1.00 | 0.59 | 0.43 | hedged possibility 0.99 |
| s8 | We discuss possible mechanisms which could affect the escape of LyC photons. | interpretation 0.78 | 0.45 | 0.03 | unclear 0.50 |
What was examined, and what was not
- arXiv listing abstract v1
- full text
- figures and tables
- references and citing sentences
- relations to other papers
- P abstract
- S sections
- T body sentences
- C citations
- R cross-paper relations
The paper
Original abstract
We present the results of rest-frame, UV slitless spectroscopic observations of a sample of 32 z~0.7 Lyman break galaxy (LBG) analogs in the COSMOS field. The spectroscopic search was performed with the Solar Blind Channel (SBC) on Hubble Space Telescope. We report the detection of leaking Lyman continuum (LyC) radiation from an AGN-starburst composite. While we find no direct detections of LyC emission in the remainder of our sample, we achieve individual lower limits (3 sigma) of the observed non-ionizing UV to LyC flux density ratios, f_{nu}(1500A)/f_{nu}(830A) of 20 to 204 (median of 73.5) and 378.7 for the stack. Assuming an intrinsic Lyman break of 3.4 and an intergalactic medium (IGM) transmission of LyC photons along the line of sight to the galaxy of 85% we report an upper limit for the relative escape fraction in individual galaxies of 0.02 - 0.19 and a stacked 3 sigma upper limit of 0.01. We find no indication of a relative escape fraction near unity as seen in some LBGs at z~3. Our UV spectra achieve the deepest limits to date at any redshift for the escape fraction in individual sources. The contrast between these z~0.7 low escape fraction LBG analogs with z~3 LBGs suggests that either the processes conducive to high escape fractions are not being selected for in the z<1 samples or the average escape fraction is decreasing from z~3 to z~1. We discuss possible mechanisms which could affect the escape of LyC photons.
Human review
References
Discussion
Know something about this paper? Leave a comment, or highlight any passage above to comment on it.