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  • 1
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    Online Resource
    JADES: Discovery of extremely high equivalent width Lyman- α emission from a faint galaxy within an ionized bubble at z = 7.3
    EDP Sciences ; 2023
    In:  Astronomy & Astrophysics Vol. 678 ( 2023-10), p. A68-
    Details
    In: Astronomy & Astrophysics, EDP Sciences, Vol. 678 ( 2023-10), p. A68-
    Abstract: We report the discovery of a remarkable Ly α emitting galaxy at z  = 7.2782, JADES-GS+53.16746−27.7720 (shortened to JADES-GS-z7-LA), with rest-frame equivalent width, EW 0 (Ly α ) = 388.0 ± 88.8 Å and UV magnitude −17.0. The spectroscopic redshift is confirmed via rest-frame optical lines [O  II ], H β and [O  III ] in its JWST/NIRSpec Micro-Shutter Assembly (MSA) spectrum. The Ly α line is detected in both lower resolution ( R  ∼ 100) PRISM as well as medium resolution ( R  ∼ 1000) G 140 M grating spectra. The line spread function-deconvolved Ly α full width at half maximum in the grating is 383.9 ± 56.2 km s −1 and the Ly α velocity offset compared to the systemic redshift is 113.3 ± 80.0 km s −1 , indicative of very little neutral gas or dust within the galaxy. We estimate the Ly α escape fraction to be 〉 70%. JADES-GS-z7-LA has a [O  III ]/[O  II ] ratio (O32) of 11.1 ± 2.2 and a ([O  III ] + [O  II ])/H β ratio (R23) of 11.2 ± 2.6, consistent with low metallicity and high ionization parameters. Deep NIRCam imaging also revealed a close companion source (separated by 0.23″), which exhibits similar photometry to that of JADES-GS-z7-LA, with a photometric excess in the F 410 M NIRCam image consistent with [O  III ] + H β emission at the same redshift. The spectral energy distribution of JADES-GS-z7-LA indicates a “bursty” star formation history, with a low stellar mass of ≈10 7   M ⊙ . Assuming that the Ly α transmission through the intergalactic medium is the same as its measured escape fraction, an ionized region of size 〉 1.5 pMpc is needed to explain the high Ly α EW and low velocity offset compared to systemic seen in JADES-GS-z7-LA. Owing to its UV-faintness, we show that it is incapable of single-handedly ionizing a region large enough to explain its Ly α emission. Therefore, we suggest that JADES-GS-z7-LA (and possibly the companion source) may be a part of a larger overdensity, presenting direct evidence of overlapping ionized bubbles at z   〉  7.
    Type of Medium: Online Resource
    ISSN: 0004-6361 , 1432-0746
    URL: Article
    DOI: 10.1051/0004-6361/202346245
    RVK:
    UA 1000
    RVK:
    US 1090
    Language: English
    Publisher: EDP Sciences
    Publication Date: 2023
    detail.hit.zdb_id: 1458466-9
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  • 2
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    JADES NIRSpec Spectroscopy of GN-z11: Lyman- α emission and possible enhanced nitrogen abundance in a z = 10.60 luminous galaxy
    EDP Sciences ; 2023
    In:  Astronomy & Astrophysics Vol. 677 ( 2023-09), p. A88-
    Details
    In: Astronomy & Astrophysics, EDP Sciences, Vol. 677 ( 2023-09), p. A88-
    Abstract: We present JADES JWST/NIRSpec spectroscopy of GN-z11, the most luminous candidate z   〉  10 Lyman break galaxy in the GOODS-North field with M UV  = −21.5. We derive a redshift of z  = 10.603 (lower than previous determinations) based on multiple emission lines in our low and medium resolution spectra over 0.7 − 5.3 μm. We significantly detect the continuum and measure a blue rest-UV spectral slope of β  = −2.4. Remarkably, we see spatially extended Lyman- α in emission (despite the highly neutral intergalactic medium expected at this early epoch), offset 555 km s −1 redwards of the systemic redshift. From our measurements of collisionally excited lines of both low and high ionisation (including [O  II ] λ 3727, [Ne  III ] λ 3869, and C  III ] λ 1909), we infer a high ionisation parameter (log U  ∼ −2). We detect the rarely seen N  IV ] λ 1486 and N  III ] λ 1748 lines in both our low and medium resolution spectra, with other high ionisation lines seen in the low resolution spectrum, such as He  II (blended with O  III ]) and C  IV (with a possible P-Cygni profile). Based on the observed rest-UV line ratios, we cannot conclusively rule out photoionisation from an active galactic nucleus (AGN), although the high C  III ]/He  II and N  III ] /He  II ratios are compatible with a star formation explanation. If the observed emission lines are powered by star formation, then the strong N  III ] λ 1748 observed may imply an unusually high N / O abundance. Balmer emission lines (H γ , H δ ) are also detected, and if powered by star formation rather than an AGN, we infer a star formation rate of ∼20 − 30 M ⊙ yr −1 (depending on the initial mass function) and low dust attenuation. Our NIRSpec spectroscopy confirms that GN-z11 is a remarkable galaxy with extreme properties seen 430 Myr after the Big Bang.
    Type of Medium: Online Resource
    ISSN: 0004-6361 , 1432-0746
    URL: Article
    DOI: 10.1051/0004-6361/202346159
    RVK:
    UA 1000
    RVK:
    US 1090
    Language: English
    Publisher: EDP Sciences
    Publication Date: 2023
    detail.hit.zdb_id: 1458466-9
    SSG: 16,12
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  • 3
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    Augmented Reality Design Heuristics: Designing for Dynamic Interactions
    SAGE Publications ; 2017
    In:  Proceedings of the Human Factors and Ergonomics Society Annual Meeting Vol. 61, No. 1 ( 2017-09), p. 2100-2104
    Details
    In: Proceedings of the Human Factors and Ergonomics Society Annual Meeting, SAGE Publications, Vol. 61, No. 1 ( 2017-09), p. 2100-2104
    Abstract: Augmented Reality (AR) has emerged as a rapidly developing technology, capable of a wide scope of applications across a variety of domains. AR technologies allow for a virtual experience to be overlaid on top of a physical environment, creating a hybrid experience in which virtual objects become a part of the user’s perceptual and physical environment. Rapid progression of the AR field requires that effective and validated methods of design evaluation be developed. Failure to consider the usability of AR applications during the design process will result in an increase in user errors and accidents, limiting user trust of the technology and undermining user perceptions of the technology, for both AR and Virtual Reality (VR) technologies (Nordrum, 2016). Through a robust and iterative process, a set of Design Heuristics for AR were developed for multidimensional augmented environments with the aim of advancing AR design methods for human factors, ergonomics, and user experience practitioners within the expanding AR community.
    Type of Medium: Online Resource
    ISSN: 2169-5067 , 1071-1813
    URL: Article
    DOI: 10.1177/1541931213602007
    Language: English
    Publisher: SAGE Publications
    Publication Date: 2017
    detail.hit.zdb_id: 2415770-3
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  • 4
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    JADES Imaging of GN-z11: Revealing the Morphology and Environment of a Luminous Galaxy 430 Myr after the Big Bang
    American Astronomical Society ; 2023
    In:  The Astrophysical Journal Vol. 952, No. 1 ( 2023-07-01), p. 74-
    Details
    In: The Astrophysical Journal, American Astronomical Society, Vol. 952, No. 1 ( 2023-07-01), p. 74-
    Abstract: We present JWST NIRCam nine-band near-infrared imaging of the luminous z = 10.6 galaxy GN-z11 from the JWST Advanced Deep Extragalactic Survey of the GOODS-N field. We find a spectral energy distribution (SED) entirely consistent with the expected form of a high-redshift galaxy: a clear blue continuum from 1.5 to 4 μ m with a complete dropout in F115W. The core of GN-z11 is extremely compact in JWST imaging. We analyze the image with a two-component model, using a point source and a Sérsic profile that fits to a half-light radius of 200 pc and an index n = 0.9. We find a low-surface-brightness haze about 0.″4 to the northeast of the galaxy, which is most likely a foreground object but might be a more extended component of GN-z11. At a spectroscopic redshift of 10.60 (Bunker et al. 2023), the comparison of the NIRCam F410M and F444W images spans the Balmer jump. From population-synthesis modeling, here assuming no light from an active galactic nucleus, we reproduce the SED of GN-z11, finding a stellar mass of ∼10 9 M ⊙ , a star formation rate of ∼20 M ⊙ yr −1 , and a young stellar age of ∼20 Myr. Since massive galaxies at high redshift are likely to be highly clustered, we search for faint neighbors of GN-z11, finding nine galaxies out to ∼5 comoving Mpc transverse with photometric redshifts consistent with z = 10.6, and a tenth more tentative dropout only 3″ away. This is consistent with GN-z11 being hosted by a massive dark-matter halo (≈8 × 10 10 M ⊙ ), though lower halo masses cannot be ruled out.
    Type of Medium: Online Resource
    ISSN: 0004-637X , 1538-4357
    URL: Article
    DOI: 10.3847/1538-4357/acdbc6
    RVK:
    UA 1000
    Language: Unknown
    Publisher: American Astronomical Society
    Publication Date: 2023
    detail.hit.zdb_id: 2207648-7
    detail.hit.zdb_id: 1473835-1
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  • 5
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    Spectroscopic confirmation of four metal-poor galaxies at z = 10.3–13.2
    Springer Science and Business Media LLC ; 2023
    In:  Nature Astronomy Vol. 7, No. 5 ( 2023-04-04), p. 622-632
    Details
    In: Nature Astronomy, Springer Science and Business Media LLC, Vol. 7, No. 5 ( 2023-04-04), p. 622-632
    Type of Medium: Online Resource
    ISSN: 2397-3366
    URL: Article
    DOI: 10.1038/s41550-023-01918-w
    Language: English
    Publisher: Springer Science and Business Media LLC
    Publication Date: 2023
    detail.hit.zdb_id: 2879712-7
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  • 6
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    Clustering with JWST: Constraining galaxy host halo masses, satellite quenching efficiencies, and merger rates at z  = 4−10
    Oxford University Press (OUP) ; 2020
    In:  Monthly Notices of the Royal Astronomical Society Vol. 493, No. 1 ( 2020-03-21), p. 1178-1196
    Details
    In: Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP), Vol. 493, No. 1 ( 2020-03-21), p. 1178-1196
    Abstract: Galaxy clustering measurements can be used to constrain many aspects of galaxy evolution, including galaxy host halo masses, satellite quenching efficiencies, and merger rates. We simulate JWST galaxy clustering measurements at z ∼ 4–10 by utilizing mock galaxy samples produced by an empirical model, the universemachine. We also adopt the survey footprints and typical depths of the planned joint NIRCam and NIRSpec Guaranteed Time Observation program planned for Cycle 1 to generate realistic JWST survey realizations and to model high-redshift galaxy selection completeness. We find that galaxy clustering will be measured with ≳5σ significance at z ∼ 4–10. Halo mass precisions resulting from Cycle 1 angular clustering measurements will be ∼0.2 dex for faint (−18 ≳ $\mathit {M}_{\mathrm{UV}}^{ }$ ≳ −19) galaxies at z ∼ 4–10 as well as ∼0.3 dex for bright ($\mathit {M}_{\mathrm{UV}}^{ }$ ∼ −20) galaxies at z ∼ 4–7. Dedicated spectroscopic follow-up over ∼150 arcmin2 would improve these precisions by ∼0.1 dex by removing chance projections and low-redshift contaminants. Future JWST observations will therefore provide the first constraints on the stellar–halo mass relation in the epoch of reionization and substantially clarify how this relation evolves at z & gt; 4. We also find that ∼1000 individual satellites will be identifiable at z ∼ 4–8 with JWST, enabling strong tests of satellite quenching evolution beyond currently available data (z ≲ 2). Finally, we find that JWST observations can measure the evolution of galaxy major merger pair fractions at z ∼ 4–8 with ∼0.1–0.2 dex uncertainties. Such measurements would help determine the relative role of mergers to the build-up of stellar mass into the epoch of reionization.
    Type of Medium: Online Resource
    ISSN: 0035-8711 , 1365-2966
    URL: Article
    DOI: 10.1093/mnras/staa324
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2020
    detail.hit.zdb_id: 2016084-7
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  • 7
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    Rest-frame UV spectroscopy of extreme [O  iii ] emitters at 1.3 〈 z 〈 3.7: toward a high-redshift UV reference sample for JWST
    Oxford University Press (OUP) ; 2021
    In:  Monthly Notices of the Royal Astronomical Society Vol. 501, No. 3 ( 2021-01-12), p. 3238-3257
    Details
    In: Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP), Vol. 501, No. 3 ( 2021-01-12), p. 3238-3257
    Abstract: Deep spectroscopy of galaxies in the reionization era has revealed intense C iii] and C iv line emission (equivalent width, EW & gt;15–20 Å). In order to interpret the nebular emission emerging at z  & gt; 6, we have begun targeting rest-frame ultraviolet (UV) emission lines in galaxies with large specific star formation rates (sSFRs) at 1.3 & lt; z & lt; 3.7. We find that C iii] reaches the EWs seen at z  & gt; 6 only in large sSFR galaxies with [O iii]+Hβ EW & gt;1500 Å. In contrast to previous studies, we find that many galaxies with intense [O iii] have weak C iii] emission (EW = 5–8 Å), suggesting that the radiation field associated with young stellar populations is not sufficient to power strong C iii]. Photoionization models demonstrate that the spread in C iii] among systems with large sSFRs ([O iii]+Hβ EW & gt;1500 Å) is driven by variations in metallicity, a result of the extreme sensitivity of C iii] to electron temperature. We find that the strong C iii] emission seen at z  & gt; 6 (EW & gt;15 Å) requires metal-poor gas (≃ 0.1 Z⊙), whereas the weaker C iii] emission in our sample tends to be found at moderate metallicities (≃ 0.3 Z⊙). The luminosity distribution of the C iii] emitters in our z ≃ 1–3 sample presents a consistent picture, with stronger emission generally linked to low-luminosity systems (MUV  & gt; −19.5) where low metallicities are more likely. We quantify the fraction of strong C iii] and C iv emitters at z ≃ 1–3, providing a baseline for comparison against z  & gt; 6 samples. We suggest that the first UV line detections at z  & gt; 6 can be explained if a significant fraction of the early galaxy population is found at large sSFR ( & gt;200 Gyr−1) and low metallicity ( & lt; 0.1 Z⊙).
    Type of Medium: Online Resource
    ISSN: 0035-8711 , 1365-2966
    URL: Article
    DOI: 10.1093/mnras/staa3454
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2021
    detail.hit.zdb_id: 2016084-7
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  • 8
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    Lyman-alpha spectroscopy of extreme [O  iii ] emitting galaxies at z ≃ 2-3: implications for Lyα visibility and LyC leakage at z 〉 6
    Oxford University Press (OUP) ; 2021
    In:  Monthly Notices of the Royal Astronomical Society Vol. 503, No. 3 ( 2021-04-05), p. 4105-4117
    Details
    In: Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP), Vol. 503, No. 3 ( 2021-04-05), p. 4105-4117
    Abstract: Spectroscopic observations of massive z & gt; 7 galaxies selected to have extremely large [O iii] + H β equivalent width (EW ∼1500 Å) have recently revealed large Ly α detection rates, in contrast to the weak emission seen in the general population. Why these systems are uniquely visible in Ly α at redshifts where the intergalactic medium (IGM) is likely significantly neutral is not clear. With the goal of better understanding these results, we have begun a campaign with MMT and Magellan to measure Ly α in galaxies with similar [O iii]  + H β EWs at z ≃ 2–3. At these redshifts, the IGM is highly ionized, allowing us to clearly disentangle how the Ly α properties depend on the [O iii] + H β EW. Here, we present Ly α EWs of 49 galaxies at z = 2.2–3.7 with intense [O iii]  + H β line emission (EW = 300–3000 Å). Our results demonstrate that strong Ly α emission (EW & gt;20 Å) becomes more common in galaxies with larger [O iii] + H β EW, reflecting a combination of increasingly efficient ionizing photon production and enhanced transmission of Ly α. Among the galaxies with the most extreme [O iii]  + H β emission (EW ∼1500 Å), we find that strong Ly α emission is not ubiquitous, with only 50 per cent of our population showing Ly α EW & gt;20 Å. Our data suggest that the range of Ly α strengths is related to the observed ellipticity, with those systems that appear edge-on or elongated having weaker Ly α emission. We use these results to interpret the anomalous Ly α properties seen in z & gt; 7 galaxies with extreme [O iii] + H β emission and discuss implications for the escape of ionizing radiation from these extreme line emitting galaxies.
    Type of Medium: Online Resource
    ISSN: 0035-8711 , 1365-2966
    URL: Article
    DOI: 10.1093/mnras/stab705
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2021
    detail.hit.zdb_id: 2016084-7
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  • 9
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    Radio and far-IR emission associated with a massive star-forming galaxy candidate at z ≃ 6.8: a radio-loud AGN in the reionization era?
    Oxford University Press (OUP) ; 2022
    In:  Monthly Notices of the Royal Astronomical Society Vol. 512, No. 3 ( 2022-04-06), p. 4248-4261
    Details
    In: Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP), Vol. 512, No. 3 ( 2022-04-06), p. 4248-4261
    Abstract: We report the identification of radio (0.144–3 GHz) and mid-, far-infrared, and sub-mm (24–850μm) emission at the position of one of 41 UV-bright ($\mathrm{M_{\mathrm{UV}}}^{ }\lesssim -21.25$) z ≃ 6.6–6.9 Lyman-break galaxy candidates in the 1.5 deg2 COSMOS field. This source, COS-87259, exhibits a sharp flux discontinuity (factor & gt;3) between two narrow/intermediate bands at 9450 and 9700 Å and is undetected in all nine bands blueward of 9600 Å, as expected from a Lyman alpha break at z ≃ 6.8. The full multiwavelength (X-ray through radio) data of COS-87529 can be self-consistently explained by a very massive (M* = 1010.8 M⊙) and extremely red (rest-UV slope β = −0.59) z ≃ 6.8 galaxy with hyperluminous infrared emission (LIR = 1013.6 L⊙) powered by both an intense burst of highly obscured star formation (SFR ≈ 1800 M⊙ yr−1) and an obscured ($\tau _{_{\mathrm{9.7\mu m}}} = 7.7\pm 2.5$) radio-loud (L1.4 GHz ≈ 1025.4 W Hz−1) active galactic nucleus (AGN). The radio emission is compact (1.04 ± 0.12 arcsec) and exhibits an ultra-steep spectrum between 1.32 and 3 GHz ($\alpha =-1.57^{+0.22}_{-0.21}$) that flattens at lower frequencies ($\alpha = -0.86^{+0.22}_{-0.16}$ between 0.144 and 1.32 GHz), consistent with known z & gt; 4 radio galaxies. We also demonstrate that COS-87259 may reside in a significant (11×) galaxy overdensity, as common for systems hosting radio-loud AGN. While we find that low-redshift solutions to the optical + near-infrared data are not preferred, a spectroscopic redshift will ultimately be required to establish the true nature of COS-87259 beyond any doubt. If confirmed to lie at z ≃ 6.8, the properties of COS-87259 would be consistent with a picture wherein AGN and highly obscured star formation activity are fairly common among very massive (M* & gt; 1010 M⊙) reionization-era galaxies.
    Type of Medium: Online Resource
    ISSN: 0035-8711 , 1365-2966
    URL: Article
    DOI: 10.1093/mnras/stac737
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2022
    detail.hit.zdb_id: 2016084-7
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  • 10
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    Strong Lyman-α emission in an overdense region at z = 6.8: a very large ( R ∼ 3 physical Mpc) ionized bubble in COSMOS?
    Oxford University Press (OUP) ; 2022
    In:  Monthly Notices of the Royal Astronomical Society Vol. 511, No. 4 ( 2022-03-10), p. 6042-6054
    Details
    In: Monthly Notices of the Royal Astronomical Society, Oxford University Press (OUP), Vol. 511, No. 4 ( 2022-03-10), p. 6042-6054
    Abstract: Our understanding of reionization has advanced considerably over the past decade, with several results now demonstrating that the intergalactic medium transitioned from substantially neutral at z = 7 to largely reionized at z = 6. However, little remains known about the sizes of ionized bubbles at z ≳ 7 as well as the galaxy overdensities which drive their growth. Fortunately, rest-ultraviolet (UV) spectroscopic observations offer a pathway towards characterizing these ionized bubbles thanks to the resonant nature of Lyman-alpha photons. In a previous work, we presented Ly α detections from three closely separated Lyman-break galaxies at z ≃ 6.8, suggesting the presence of a large (R & gt; 1 physical Mpc) ionized bubble in the 1.5 deg2 COSMOS field. Here, we present new deep Ly α spectra of 10 UV-bright ($\mathrm{\mathit{ M}}_{\mathrm{UV}}^{} \le -20.4$) z ≃ 6.6–6.9 galaxies in the surrounding area, enabling us to better characterize this potential ionized bubble. We confidently detect (S/N & gt; 7) Ly α emission at z = 6.701–6.882 in nine of ten observed galaxies, revealing that the large-scale volume spanned by these sources (characteristic radius R = 3.2 physical Mpc) traces a strong galaxy overdensity (N/〈N〉 ≳ 3). Our data additionally confirm that the Ly α emission of UV-bright galaxies in this volume is significantly enhanced, with 40 per cent (4/10) showing strong Ly α emission (equivalent width & gt;25 Å) compared to the 8–9 per cent found on average at z ∼ 7. The median Ly α equivalent width of our observed galaxies is also ≈2 times that typical at z ∼ 7, consistent with expectations if a very large (R ∼ 3 physical Mpc) ionized bubble is allowing the Ly α photons to cosmologically redshift far into the damping wing before encountering H i.
    Type of Medium: Online Resource
    ISSN: 0035-8711 , 1365-2966
    URL: Article
    DOI: 10.1093/mnras/stac524
    Language: English
    Publisher: Oxford University Press (OUP)
    Publication Date: 2022
    detail.hit.zdb_id: 2016084-7
    SSG: 16,12
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