The Keck Cosmic Web Imager Integral Field Spectrograph

Morrissey, Patrick; Matuszewski, Matuesz; Martin, D. Christopher; Neill, James D.; Epps, Harland W.; Fucik, Jason; Weber, B. L.; Darvish, Behnam; Adkins, Sean M.; Allen, S. L.; Bartos, Randy; Belicki, Justin; Cabak, Jerry; Callahan, Shawn; Cowley, Dave; Crabill, Marty; Deich, Willian; Delecroix, Alex; Doppman, Greg; Hilyard, David F.; James, Ean; Kaye, Steve; Kokorowski, M.; Kwok, S.; Lanclos, Kyle; Milner, Steve; Moore, Anna; O’Sullivan, Donal; Parihar, Prachi; Park, Sam; Phillips, Andrew C.; Rizzi, L.; Rockosi, Constance M.; Rodríguez, Héctor; Salaün, Yves; Seaman, Kirk; Sheikh, David; Weiss, Jason; Zarzaca, Ray

doi:10.3847/1538-4357/aad597

Cited by 178 publications

(130 citation statements)

References 39 publications

Supporting

Mentioning

121

Contrasting

Order By: Relevance

“…On UT 04 October 2018, we executed a Target of Opportunity observation of the field surrounding FRB 180924 with the Keck Cosmic Web Imager (KCWI; Ref. (61)) instrument on the W.M. Keck II telescope.…”

Section: S19 Keck-kcwi Integral-field Spectroscopymentioning

confidence: 99%

A single fast radio burst localized to a massive galaxy at cosmological distance

Bannister

Deller

Phillips

et al. 2019

Science

400

353

View full text Add to dashboard Cite

Fast Radio Bursts (FRBs) are brief radio emissions from distant astronomical sources. Some are known to repeat, but most are single bursts. Non-repeating FRB observations have had insufficient positional accuracy to localize them to an individual host galaxy. We report the interferometric localization of the single pulse FRB 180924 to a position 4 kpc from the center of a luminous galaxy at redshift 0.3214. The burst has not been observed to repeat. The properties of the burst and its host are markedly different from the only other accurately localized FRB source. The integrated electron column density along the line of sight closely matches models of the intergalactic medium, indicating that some FRBs are clean probes of the baryonic component of the cosmic web.Cosmological observations have shown that baryons comprise 4% of the energy density of the Universe, of which only about 10% is in cold gas and stars (1), with the remainder residing in a diffuse plasma surrounding and in between galaxies and galaxy clusters. The location and density of this material has been challenging to characterize, and up to 50% of it remains unaccounted (2).Fast radio bursts (FRBs; ref.(3)) are bright bursts of radio waves with millisecond duration. They can potentially be used to detect, study, and map this medium, as bursts of emission are dispersed and scattered by their 1 arXiv:1906.11476v1 [astro-ph.HE] 27 Jun 2019 dual-polarization beams on the sky using digital beamforming, producing a total field-of-view of ∼ 30 deg 2 . For burst detection, the beamformers produces channelized autocorrelation spectra for both linear polarizations of all beams, with an integration time of 864 µs and channel bandwidth of 1 MHz in these observations. We used 336 channels centered at 1320 MHz. A real-time detection pipeline incoherently adds the spectra from all available antennas (24 antennas in these observations) and polarization channels, then searches (16) the result for dispersed pulses (17).Burst localization is completed with a second data product that utilizes both the amplitude and phase information of the burst radiation. The beamformers store samples of the complex electric field for all beams and both polarizations in a ring buffer of 3.1 s duration, with the oldest data being continuously overwritten by new data. The data are saved for offline interferometric analysis only when the pipeline identifies a candidate. For the searches reported here the triggering required pulses with widths less than 9 ms and S/N > 10.Previous searches with ASKAP used antennas pointed in different directions to maximize sky coverage (10,16). In contrast, our observations used antennas all pointed in the same direction, enabling the array to act as an interferometer capable of sub-arcsecond localization with a 30 deg 2 field of view. We targeted high Galactic latitude fields (Galactic latitude |b| ∼ 50 • ), that had been observed previously (10, 16), and Southern circumpolar fields. The high-latitude fields were observed regularly through 2017 and earl...

show abstract

Section: S19 Keck-kcwi Integral-field Spectroscopymentioning

confidence: 99%

A single fast radio burst localized to a massive galaxy at cosmological distance

Bannister

Deller

Phillips

et al. 2019

Science

400

353

View full text Add to dashboard Cite

show abstract

“…The KCWI pipeline v1.0 * , released in Mar. 17, 2018 was adopted to reduce our data (Morrissey et al 2018;Cai et al 2018). For each image, we first subtracted the bias, correcting the pixel-to-pixel variation using flatfield images, removing cosmic-rays, and error image creation.…”

Section: Kcwi Standard Pipelinementioning

confidence: 99%

Evolution of the Cool Gas in the Circumgalactic Medium of Massive Halos: A Keck Cosmic Web Imager Survey of Lyα Emission around QSOs at z ≈ 2

Cai¹,

Cantalupo²,

Prochaska³

et al. 2019

ApJS

112

122

View full text Add to dashboard Cite

Motivated by the recent discovery of the near-ubiquity of Lyα emission around z 3 QSOs, we performed a systematic study of QSO circumgalactic Lyα emission at z ≈ 2, utilizing the unique capability of the Keck Cosmic Web Imager (KCWI) -a new wide-field, blue sensitive integral-field spectrograph (IFU). In this paper, we present KCWI observations on a sample of 16 ultraluminous Type-I QSOs at z = 2.1 − 2.3 with ionizing luminosities of L νLL = 10 31.1−32.3 erg s −1 Hz −1 . We found that 14 out of 16 QSOs are associated with Lyα nebulae with projected linear-sizes larger than 50 physical kpc (pkpc). Among them, four nebulae have enormous Lyα emission with the Lyα surface brightness SB Lyα > 10 −17 erg s −1 cm −2 arcsec −2 on the > 100 kpc scale, extending beyond the field of view of KCWI. Our KCWI observations reveal that most z ≈ 2 QSO nebulae have a more irregular morphology compared to those at z 3. In turn, we measure that the circularlyaveraged surface brightness (SB) at z ≈ 2 is 0.4 dex fainter than the redshift-corrected, median SB at z 3. The Lyα SB profile (SB Lyα ) of QSOs at z ≈ 2 can be described by a power law of SB Lyα,z≈2.3 = 3.7 × 10 −17 × (r/40) −1.8 erg s −1 cm −2 arcsec −2 , with the slope similar to that at z 3. The observed lower redshift-corrected, circularly-averaged SB may be mainly due to the lower covering factor of cool gas clouds in massive halos at z ≈ 2.

show abstract

“…These limitations have recently been lifted by integral field spectrographs which have been deployed at the largest observing facilities, including the Multi Unit Spectroscopic Explorer (MUSE; Bacon et al 2010) at the ESO Very Large Telescope, and the Keck Cosmic Web Imager (KCWI; Morrissey et al 2018) at the Keck Observatory. In particular, thanks to its large 1 arcmin 2 field of view, its extended wavelength coverage in the optical, and its exquisite sensitivity, MUSE has become the ideal instrument for studies of the CGM of galaxies in quasar fields (e.g.…”

mentioning

confidence: 99%

The MUSE Ultra Deep Field (MUDF). II. Survey design and the gaseous properties of galaxy groups at 0.5 < z < 1.5

Fossati

Fumagalli

Lofthouse

et al. 2019

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

We present the goals, design, and first results of the MUSE Ultra Deep Field (MUDF) survey, a large programme using the Multi Unit Spectroscopic Explorer (MUSE) instrument at the ESO Very Large Telescope. The MUDF survey is collecting ≈ 150 hours on-source of integral field optical spectroscopy in a 1.5 × 1.2 arcmin 2 region which hosts several astrophysical structures along the line of sight, including two bright z ≈ 3.2 quasars with close separation (≈ 500 kpc). Following the description of the data reduction procedures, we present the analysis of the galaxy environment and gaseous properties of seven groups detected at redshifts 0.5 < z < 1.5, spanning a large dynamic range in halo mass, log(M h /M ) ≈ 11 − 13.5. For four of the groups, we find associated Mg ii absorbers tracing cool gas in high-resolution spectroscopy of the two quasars, including one case of correlated absorption in both sightlines at distance ≈ 480 kpc. The absorption strength associated with the groups is higher than what has been reported for more isolated galaxies of comparable mass and impact parameters. We do not find evidence for widespread cool gas giving rise to strong absorption within these groups. Combining these results with the distribution of neutral and ionised gas seen in emission in lower-redshift groups, we conclude that gravitational interactions in the group environment strip gas from the galaxy haloes into the intragroup medium, boosting the cross section of cool gas and leading to the high fraction of strong Mg ii absorbers that we detect.

show abstract

The Keck Cosmic Web Imager Integral Field Spectrograph

Cited by 178 publications

References 39 publications

A single fast radio burst localized to a massive galaxy at cosmological distance

A single fast radio burst localized to a massive galaxy at cosmological distance

Evolution of the Cool Gas in the Circumgalactic Medium of Massive Halos: A Keck Cosmic Web Imager Survey of Lyα Emission around QSOs at z ≈ 2

The MUSE Ultra Deep Field (MUDF). II. Survey design and the gaseous properties of galaxy groups at 0.5 < z < 1.5

Contact Info

Product

Resources

About

The Keck Cosmic Web Imager Integral Field Spectrograph

Cited by 178 publications

References 39 publications

A single fast radio burst localized to a massive galaxy at cosmological distance

A single fast radio burst localized to a massive galaxy at cosmological distance

Evolution of the Cool Gas in the Circumgalactic Medium of Massive Halos: A Keck Cosmic Web Imager Survey of Lyα Emission around QSOs at z ≈ 2

The MUSE Ultra Deep Field (MUDF). II. Survey design and the gaseous properties of galaxy groups at 0.5 &lt; z &lt; 1.5

Contact Info

Product

Resources

About

The MUSE Ultra Deep Field (MUDF). II. Survey design and the gaseous properties of galaxy groups at 0.5 < z < 1.5