<i>HUBBLE SPACE TELESCOPE</i>IMAGING OF Lyα EMISSION AT<i>z</i>≈ 4.4

Finkelstein, Steven L.; Cohen, Seth H.; Windhorst, Rogier A.; Ryan, Russell E.; Hathi, N. P.; Finkelstein, Keely D.; Anderson, Jay; Grogin, Norman A.; Koekemoer, Anton M.; Malhotra, Sangeeta; Mutchler, Max; Rhoads, James E.; McCarthy, Patrick J.; O’Connell, R. W.; Balick, Bruce; Bond, Howard E.; Calzetti, Daniela; Disney, M. J.; Dopita, Michael A.; Frogel, J. A.; Hall, Donald N. B.; Holtzman, Jon A.; Kimble, Randy A.; Paresce, Francesco; Saha, Abhijit; Silk, Joseph; Trauger, John T.; Walker, A. R.; Whitmore, Bradley C.; Young, Erick T.

doi:10.1088/0004-637x/735/1/5

Cited by 37 publications

(53 citation statements)

References 41 publications

(66 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Bond et al (2010 suggested Lyα sizes are compact and similar to UV emission; but Finkelstein et al (2011) suggested the half light radius of Lyα appears ∼1.6 times larger than the half light radius of UV continuum. These narrow band HST images of high-z LAEs are very hard to get and have low S/N ratios, thus the Lyα and UV sizes of low-z LAEs are valuable.…”

Section: Comparing Spatial Profiles Of Lyα Photons At Different Velocmentioning

confidence: 99%

Lyα and UV Sizes of Green Pea Galaxies

Yang

Malhotra

Rhoads

et al. 2017

ApJ

Self Cite

View full text Add to dashboard Cite

Green Peas are nearby analogs of high-redshift Lyα-emitting galaxies (LAEs). To probe their Lyα escape, we study the spatial profiles of Lyα and UV continuum emission of 24 Green Pea galaxies using the Cosmic Origins Spectrograph (COS) on Hubble Space Telescope (HST). We extract the spatial profiles of Lyα emission from their 2D COS spectra, and of UV continuum from both the 2D spectra and NUV images. The Lyα emission shows more extended spatial profiles than the UV continuum in most Green Peas. The deconvolved Full Width Half Maximum (FWHM) of the Lyα spatial profile is about 2 to 4 times that of the UV continuum in most cases. Since Green Peas are analogs of high-z LAEs, it suggests that most high-z LAEs likely have larger Lyα sizes than UV sizes. We also compare the spatial profiles of Lyα photons at blueshifted and redshifted velocities in eight Green Peas with sufficient data quality, and find the blue wing of the Lyα line has a larger spatial extent than the red wing in four Green Peas with comparatively weak blue Lyα line wings. We show that Green Peas and MUSE z = 3 − 6 LAEs have similar Lyα and UV continuum sizes, which probably suggests starbursts in both low-z and high-z LAEs drive similar gas outflows illuminated by Lyα light. Five Lyman continuum (LyC) leakers in this sample have similar Lyα to UV continuum size ratios (∼ 1.4 − 4.3) to the other Green Peas, indicating their LyC emission escape through ionized holes in the interstellar medium.

show abstract

Section: Comparing Spatial Profiles Of Lyα Photons At Different Velocmentioning

confidence: 99%

Lyα and UV Sizes of Green Pea Galaxies

Yang

Malhotra

Rhoads

et al. 2017

ApJ

Self Cite

View full text Add to dashboard Cite

show abstract

“…However, because the line of sight passes through the galaxy, the systemic redshift can be well estimated from the absorption lines, unlike LBGs that have ISM absorption Finkelstein et al 2011;Hashimoto et al 2013). Bottom: cross-correlation function obtained by correlating the Lyman-break galaxy and the ESDLA (3σ-clipped mean luminosity) composites at different velocities.…”

Section: Ly α Profilementioning

confidence: 99%

A connection between extremely strong damped Lyman-αsystems and Lyman-αemitting galaxies at small impact parameters

Noterdaeme

Petitjean

Pâris

et al. 2014

A&A

107

View full text Add to dashboard Cite

We present a study of ∼100 high redshift (z ∼ 2−4) extremely strong damped Lyman-α systems (ESDLA, with N(H i) ≥ 0.5 × 10 22 cm −2 ) detected in quasar spectra from the Baryon Oscillation Spectroscopic Survey (BOSS) of the Sloan Digital Sky Survey (SDSS-III) Data Release 11. We study the neutral hydrogen, metal, and dust content of this elusive population of absorbers and confirm our previous finding that the high column density end of the N(H i) frequency distribution has a relatively shallow slope with power-law index −3.6, similar to what is seen from 21-cm maps in nearby galaxies. The stacked absorption spectrum indicates a typical metallicity ∼1/20th solar, similar to the mean metallicity of the overall DLA population. The relatively small velocity extent of the low-ionisation lines suggests that ESDLAs do not arise from large-scale flows of neutral gas. The high column densities involved are in turn more similar to what is seen in DLAs associated with gamma-ray burst afterglows (GRB-DLAs), which are known to occur close to star-forming regions. This indicates that ESDLAs arise from a line of sight passing at very small impact parameters from the host galaxy, as observed in nearby galaxies. This is also supported by simple theoretical considerations and recent high-z hydrodynamical simulations. We strongly substantiate this picture by the first statistical detection of Ly α emission with L ESDLA (Ly α) (0.6 ± 0.2) × 10 42 erg s −1 in the core of ESDLAs (corresponding to about 0.1 L at z ∼ 2−3), obtained through stacking the fibre spectra (of radius 1 corresponding to ∼8 kpc at z ∼ 2.5). Statistical errors on the Ly α luminosity are of the order of 0.1 × 10 42 erg s −1 but we caution that the measured Ly α luminosity may be overestimated by ∼35% due to sky light residuals and/or FUV emission from the quasar host and that we have neglected flux-calibration uncertainties. We estimate a more conservative uncertainty of 0.2 × 10 42 erg s −1 . The properties of the Ly α line (luminosity distribution, velocity width and velocity offset compared to systemic redshift) are very similar to that of the population of Lyman-α emitting galaxies (LAEs) with L LAE (Ly α) ≥ 10 41 erg s −1 detected in long-slit spectroscopy or narrow-band imaging surveys. By matching the incidence of ESDLAs with that of the LAEs population, we estimate the high column density gas radius to be about r gas = 2.5 kpc, i.e., significantly smaller than the radius corresponding to the BOSS fibre aperture, making fibre losses likely negligible. Finally, the average measured Ly α luminosity indicates a star-formation rate consistent with the Schmidt-Kennicutt law, SFR (M yr −1 ) ≈ 0.6/ f esc , where f esc < 1 is the Ly α escape fraction. Assuming the typical escape fraction of LAEs, f esc ∼ 0.3, the Schmidt-Kennicutt law implies a galaxy radius of about r gal ≈ 2.5 kpc. Finally, we note that possible overestimation of the Ly α emission would result in both smaller r gas and r gal . Our results support a close association between LAEs and stro...

show abstract

“…However, the detected haloes (r e ∼ 8 kpc at z = 2.2) were not as extended as the ones claimed by S11 (r e ∼ 25 kpc at z = 2.65). A few attempts to detect Lyα haloes from individual high-z LAEs were performed by Bond et al (2010) and Finkelstein et al (2011a) in HST-filter images. Bond et al (2010) presented a morphological study of LAE Lyα emission at z 3.1 (F502N filter, 1σ detection limit of 3E-17 erg s −1 cm −2 arcsec −2 for 1 arcsec source).…”

Section: Rauchmentioning

confidence: 99%

“…Their images were very shallow and did not show significant extended haloes (ξ(Lyα/UV) ∼ 1, Table 5). An estimation at z ∼ 4.5 was presented in Finkelstein et al (2011a) (F658N filter, 1σ detection limit of about 2E-18 erg s −1 cm −2 for 1 arcsec source). They studied Lyα emission from three spectroscopically confirmed LAEs and found evidence of Lyα haloes in two of them (ξ(Lyα/UV) ∼1.5).…”

Section: Rauchmentioning

confidence: 99%

“…Also, this source was composed of two main clumps both in the rest-frame UV and in Lyα. Finkelstein et al (2011a) spatially resolved three spectroscopically confirmed LAEs placed at z 4.5 (observedframe λ(Lyα) ∼ 6570 Å) by using the HST Advanced Camera for Surveys (ACS) F658N narrow band. Two out of the three systems showed Lyα emission significantly more extended than the UV continuum.…”

Section: Introductionmentioning

confidence: 97%

See 1 more Smart Citation

The Lyman alpha reference sample

Guaita

Melinder

Hayes

et al. 2015

A&A

View full text Add to dashboard Cite

Context. The transport of Lyα photons in galaxies is a complex process and the conditions under which Lyα photons manage to escape from certain galaxies is still under investigation. The Lyman alpha reference sample (LARS) is a sample of 14 local starforming galaxies, designed to study Lyα in detail and relate it to rest-frame UV and optical emission. Aims. With the aim of identifying rest-frame UV and optical properties, which are typical of Lyα emitters (LAEs, galaxies with EW(Lyα) > 20 Å) at both low and high redshift, we investigated the morphological properties of the LARS galaxies, in particular the ones that exhibit intense Lyα radiation. Methods. We measured sizes and morphological parameters in the continuum, Lyα, and Hα images. We studied morphology by using the Gini coefficient vs. M20 and asymmetry vs. concentration diagrams. We then simulated LARS galaxies at z ∼ 2 and 5.7, performing the same morphological measurements. We also investigated the detectability of LARS galaxies in current deep field observations. The subsample of LAEs within LARS (LARS-LAEs) was stacked to provide a comparison to stacking studies performed at high redshift. Results. LARS galaxies have continuum size, stellar mass, and rest-frame absolute magnitude typical of Lyman break analogues in the local Universe and also similar to 2 < z < 3 star-forming galaxies and massive LAEs. LARS optical morphology is consistent with the one of merging systems, and irregular or starburst galaxies. For the first time we quantify the morphology in Lyα images: even if a variety of intrinsic conditions of the interstellar medium can favour the escape of Lyα photons, LARS-LAEs appear small in the continuum, and their Lyα is compact. LARS galaxies tend to be more extended in Lyα than in the rest-frame UV. It means that Lyα photons escape by forming haloes around HII regions of LARS galaxies. Conclusions. The stack of LARS-LAE Lyα images is peaked in the centre, indicating that the conditions, which make a galaxy an LAE, tend to produce a concentrated surface brightness profile. On the other hand, the stack of all LARS galaxies is shallower and more extended. This can be caused by the variety of dust and HI amount and distribution, which produces a more complex, patchy, and extended profile, like the one observed for Lyman break galaxies that can contribute to the stack. We cannot identify a single morphological property that controls whether a galaxy emits a net positive Lyα flux. However, the LARS-LAEs have continuum properties consistent with merging systems.

show abstract

HUBBLE SPACE TELESCOPEIMAGING OF Lyα EMISSION ATz≈ 4.4

Cited by 37 publications

References 41 publications

Lyα and UV Sizes of Green Pea Galaxies

Lyα and UV Sizes of Green Pea Galaxies

A connection between extremely strong damped Lyman-αsystems and Lyman-αemitting galaxies at small impact parameters

The Lyman alpha reference sample

Contact Info

Product

Resources

About