标题： 一个窄带成像搜索用于红移大于3的星系的[OIII]发射 显示英文标题

标题： A Narrowband Imaging Search for [OIII] Emission from Galaxies at z>3

摘要： 我们呈现了在红移处进行的QSO区域窄带调查的结果，该红移使[OIII](5007)发射线位于1% 2.16微米滤光片中。 我们观测了3平方角分，并在PC 1109+4642周围的区域检测到一个发射线候选天体。 我们讨论了该天体可能是位于QSO红移z_em=3.313的星形成星系，或是一个塞弗特星系的可能性。 在前一种情况下，我们推断这个Kprime=21.3的天体的恒星形成速率为170 Msun/yr。 该星系具有紧凑但可分辨的形态，FWHM=0.6弧秒，或在z=3.313时为4.2kpc（H_0=50 km/s/Mpc和q_0=0.5）。 QSO环境中此类天体的共动密度似乎为0.0033Mpc^3，略低于（<= 3sigma）在z~2.5的吸收线场中观测到的Halpha发射体的密度，但与z~3的Lyman Break星系的密度相似。 如果另一方面，大部分的线发射来自红移为3.31的塞弗特2型核，则高推断体积密度可能意味着从当前时期塞弗特2型光度函数的大演化。 我们发现包含该天体的区域在Kprime图像中还包含许多暗弱的扩展天体，但没有显著超过预期的数量-星等关系的过剩。 我们讨论了发射线可能是在较低红移的更长波长线的含义。 显示英文摘要

摘要： We present the results of a narrow-band survey of QSO fields at redshifts that place the [OIII](5007) emission line in the 1% 2.16micron filter. We have observed 3 square arcminutes and detected one emission line candidate object in the field around PC 1109+4642. We discuss the possibilities that this object is a star-forming galaxy at the QSO redshift, z_em=3.313 or a Seyfert galaxy. In the former case, we infer a star formation rate of 170 Msun/yr for this Kprime=21.3 object. The galaxy has a compact but resolved morphology, with a FWHM=0.6arcs, or 4.2kpc at z=3.313 (H_0=50 km/s/Mpc and q_0=0.5). The comoving density of such objects in QSO environments appears to be 0.0033Mpc^3, marginally lower (<= 3sigma) than the density observed for Halpha-emitters in absorption-line fields at z~2.5, but similar to the density of Lyman Break Galaxies at z~3. If on the other hand, most of the line emission is [OIII] from a Seyfert 2 nucleus at z=3.31, then the high inferred volume density could imply a large evolution in the Seyfert 2 luminosity function from the current epoch. We find the field containing the object to also contain many faint extended objects in the Kprime image, but little significant excess over the expected number-magnitude relation. We discuss the implication of the emission line being a longer wavelength line at a lower redshift.