English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Tools annual

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

We conduct a deep narrow-band imaging survey of 13 Ly$\alpha$ blobs (LABs)located in the SSA22 proto-cluster at z~3.1 in the CIV and HeII emission linesin an effort to constrain the physical process powering the Ly$\alpha$ emissionin LABs. Our observations probe down to unprecedented surface brightness limitsof 2.1 $-$ 3.4 $\times$ 10$^{-18}$ erg s$^{-1}$ cm$^{-2}$ arcsec$^{-2}$ per 1arcsec$^2$ aperture (5$\sigma$) for the HeII$\lambda$1640 and CIV$\lambda$1549lines, respectively. We do not detect extended HeII and CIV emission in any ofthe LABs, placing strong upper limits on the HeII/Ly$\alpha$ and CIV/Ly$\alpha$line ratios, of 0.11 and 0.16, for the brightest two LABs in the field. Weconduct detailed photoionization modeling of the expected line ratios and findthat, although our data constitute the deepest ever observations of theselines, they are still not deep enough to rule out a scenario where theLy$\alpha$ emission is powered by the ionizing luminosity of an obscured AGN.Our models can accommodate HeII/Ly$\alpha$ and CIV/Ly$\alpha$ ratios as low as$\simeq$0.05 and $\simeq$0.07 respectively, implying that one needs to reachsurface brightness as low as 1 $-$ 1.5 $\times$ 10$^{-18}$ erg s$^{-1}$cm$^{-2}$ arcsec$^{-2}$ (at 5$\sigma$) in order to rule out a photoionizationscenario. These depths will be achievable with the new generation ofimage-slicing integral field units such as VLT/MUSE or Keck/KCWI. We also modelthe expected HeII/Ly$\alpha$ and CIV/Ly$\alpha$ in a different scenario, whereLy$\alpha$ emission is powered by shocks generated in a large-scale superwind,but find that our observational constraints can only be met for shockvelocities $v_{\rm s} \gtrsim$ 250 km s$^{-1}$, which appear to be in conflictwith recent observations of quiescent kinematics in LABs.

A Deep Narrowband Imaging Search for CIV and He II Emission from Ly$\alpha$ Blobs