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Browsing by Author "Eisenhardt, P."

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    A New Population of High-z, Dusty Lyα Emitters and Blobs Discovered by WISE: Feedback Caught in the Act?
    Bridge, C. R.; Blain, A.; Borys, C. J. K.; Petty, S.; Benford, D.; Eisenhardt, P.; Farrah, D.; Griffith, R. L.; Jarrett, T.; Lonsdale, C.; Stanford, S. A.; Stern, D.; Tsai, C. W.; Wright, E. L.; Wu, J. W. (IOP PUBLISHING LTD, 2013-06)
    By combining data from the NASA Wide-field Infrared Survey Explorer (WISE) mission with optical spectroscopy from the W. M. Keck telescope, we discover a mid-IR color criterion that yields a 78% success rate in identifying rare, typically radio-quiet, 1.6 less than or similar to z less than or similar to 4.6 dusty Ly alpha emitters (LAEs). Of these, at least 37% have emission extended on scales of 30-100 kpc and are considered Ly alpha "blobs" (LABs). The objects have a surface density of only similar to 0.1 deg(-2), making them rare enough that they have been largely missed in deep, small area surveys. We measured spectroscopic redshifts for 92 of these galaxies, and find that the LAEs (LABs) have a median redshift of 2.3 (2.5). The WISE photometry coupled with data from Herschel (Herschel is an ESA space observatory with science instruments provided by European-led Principal Investigator consortia and with important participation from NASA) reveals that these galaxies are in the Hyper Luminous IR galaxy regime (L-IR greater than or similar to 10(13)-10(14) L-circle dot) and have warm colors. They are typically more luminous and warmer than other dusty, z similar to 2 populations such as submillimeter-selected galaxies and dust-obscured galaxies. These traits are commonly associated with the dust being illuminated by intense active galactic nucleus activity. We hypothesize that the combination of spatially extended Ly alpha, large amounts of warm IR-luminous dust, and rarity (implying a short-lived phase) can be explained if the galaxies are undergoing brief, intense "feedback" transforming them from an extreme dusty starburst/QSO into a mature galaxy.
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    WISE detections of known QSOs at redshifts greater than six
    Blain, A. W.; Assef, R.; Stern, D.; Tsai, C. W.; Eisenhardt, P.; Bridge, C. R.; Benford, D.; Jarrett, T.; Cutri, R.; Petty, S.; Wu, J. W.; Wright, E. L. (IOP Publishing Ltd., 2013-12)
    We present WISE All-Sky mid-infrared (IR) survey detections of 55% (17/31) of the known QSOs at z > 6 from a range of surveys: the SDSS, the CFHT-LS, FIRST, Spitzer, and UKIDSS. The WISE catalog thus provides a substantial increase in the quantity of IR data available for these sources: 17 are detected in the WISE W1 (3.4 mu m) band, 16 in W2 (4.6 mu m), 3 in W3 (12 mu m), and 0 in W4 (22 mu m). This is particularly important with Spitzer in its warm-mission phase and no faint follow-up capability at wavelengths longward of 5 mu m until the launch of James Webb Space Telescope (JWST). WISE thus provides a useful tool for understanding QSOs found in forthcoming large-area optical/IR sky surveys using PanSTARRS, SkyMapper, VISTA, DES, and LSST. The rest-UV properties of the WISE-detected and the WISE-non-detected samples differ: the detections have brighter i/z-band magnitudes and redder rest-UV colors. This suggests that a more aggressive hunt for very high redshift QSOs by combining WISE W1 and W2 data with red, observed optical colors could be effective at least for a subset of dusty candidate QSOs. Stacking the WISE images of the WISE-non-detected QSOs indicates that they are, on average, significantly fainter than the WISE-detected examples, and are thus not narrowly missing detection in the WISE catalog. The WISE catalog detection of three of our sample in the W3 band indicates that their mid-IR flux can be detected individually, although there is no stacked W3 detection of sources detected in W1 but not W3. Stacking analyses of WISE data for large active galactic nucleus samples will be a useful tool, and high-redshift QSOs of all types will be easy targets for JWST.