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 present Spitzer observations of Lya Blobs (LAB) at z=2.38-3.09. Themid-infrared ratios (4.5/8um and 8/24um) indicate that ~60% of LAB infraredcounterparts are cool, consistent with their infrared output being dominated bystar formation and not active galactic nuclei (AGN). The rest have asubstantial hot dust component that one would expect from an AGN or an extremestarburst. Comparing the mid-infrared to submillimeter fluxes (~850um or restframe far infrared) also indicates a large percentage (~2/3) of the LABcounterparts have total bolometric energy output dominated by star formation,although the number of sources with sub-mm detections or meaningful upperlimits remains small (~10). We obtained Infrared Spectrograph (IRS) spectra of6 infrared-bright sources associated with LABs. Four of these sources havemeasurable polycyclic aromatic hydrocarbon (PAH) emission features, indicativeof significant star formation, while the remaining two show a featurelesscontinuum, indicative of infrared energy output completely dominated by an AGN.Two of the counterparts with PAHs are mixed sources, with PAH line-to-continuumratios and PAH equivalent widths indicative of large energy contributions fromboth star formation and AGN. Most of the LAB infrared counterparts have largestellar masses, around 10^11 Mo. There is a weak trend of mass upper limit withthe Lya luminosity of the host blob, particularly after the most likely AGNcontaminants are removed. The range in likely energy sources for the LABs foundin this and previous studies suggests that there is no single source of powerthat is producing all the known LABs.

PAH Emission Within Lyman Alpha Blobs