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Event rate of long Gamma-Ray Bursts (GRBs) is expected to be an useful tracer of the cosmic star-formation history. For this purpose, it is necessary to understand what kind of star formations/galaxies are traced by GRBs. Here we report rest-frame far-infrared (FIR) continuum detections of GRB 070521 and 080207 host galaxies at $zsim2$ with ALMA band 8 and 9. The FIR photometries provide the reliable star-formation rates (SFRs), because FIR emission is free from dust extinction and possible radio contamination from long-lived afterglows of GRBs. The spectral energy distribution fittings indicate 49.85$^{+72.33}_{-2.86}$ and 123.4$^{+25.19}_{-21.78}$ $M_{odot}$ yr$^{-1}$ for the 070521 and 080207 hosts, respectively. The derived SFRs place them on the lq lq main sequencerq rq of normal star-forming galaxies at $zsim2$. The derived SFRs are significantly lower than that of radio observations. It is inferred that the observed radio fluxes in a previous study are contaminated by the afterglows. ALMA marginally detected [C~{sc ii}],158,$mu$m emission line from the GRB 080207 host galaxy with S/N $sim$ 4. This is the first detection of [C~{sc ii}],158,$mu$m of a GRB host at $z>2$, and the second detection among known GRBs. The luminosity ratio of [C~{sc~ii}],158$mu$m to FIR is 7.5$times 10^{-4}$, which is one of the smallest values among galaxies at $zsim 1-2$ with the same FIR luminosity. The lq lq [C~{sc ii}] deficitrq rq could be a new physical property to characterise GRB hosts at $zsim1-2$. Possible parameters controlling the deficit include the metallicity, initial mass function, and gas density.
Gamma-Ray Bursts (GRBs) can be a promising tracer of cosmic star-formation rate history (CSFRH). In order to reveal the CSFRH using GRBs, it is important to understand whether they are biased tracers or not. For this purpose, it is crucial to underst
We present high resolution (0.3) Atacama Large Millimeter Array (ALMA) 870um imaging of five z~1.5-4.5 X-ray detected AGN with luminosities of L(2-8keV)>10^42 erg/s. These data provide a >~20x improvement in spatial resolution over single-dish rest-f
Star formation rate (SFR) measurements at z>4 have relied mostly on rest-frame far-ultraviolet (FUV) observations. The corrections for dust attenuation based on IRX-$beta$ relation are highly uncertain and are still debated in the literature. Hence,
We present a study of the [CII] 158micron line and underlying far-infrared (FIR) continuum emission of 27 quasar host galaxies at z~6, traced by the Atacama Large Millimeter/submillimeter Array at a spatial resolution of ~1 physical kpc. The [CII] em
We present dust attenuation properties of spectroscopically confirmed star forming galaxies on the main sequence at a redshift of ~4.4-5.8. Our analyses are based on the far infrared continuum observations of 118 galaxies at rest-frame 158{mu}m obtai