The<i>Herschel</i>Lensing Survey (HLS): Overview

Egami, Eiichi; Rex, M.; Rawle, Tim; Pérez‐González, Pablo G.; Richard, Johan; Kneib, Jean-Paul; Schaerer, D.; Altiéri, B.; Valtchanov, I.; Blain, A. W.; Fadda, D.; Zemcov, M.; Bock, J. J.; Boone, F.; Bridge, Carrie; Clément, Benjamin; Combes, F.; Dessauges‐Zavadsky, M.; Dowell, C. D.; Ilbert, O.; Ivison, R. J.; Jauzac, Mathilde; Lutz, D.; Metcalfe, L.; Omont, A.; Pelló, R.; Pereira, M. J.; Rieke, G. H.; Rodighiero, G.; Smail, Ian; Smith, Graham P.; Tramoy, G.; Walth, Gregory; Werf, P. van der; Werner, M. W.

doi:10.1051/0004-6361/201014696

Cited by 96 publications

(65 citation statements)

References 32 publications

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“…We can further compare our noise estimates to those from other Herschel observations of similar depth. For example, the Herschel lensing survey 40 reported a 1-σ point-source depth of 2.4 mJy at 250 µm and 3.4 mJy at 350 µm for on-source exposure per sky position of 36 mins with position priors from short wavelengths, compared to our 2-4 mJy at 250 µm and 3-5 mJy at 250 µm for our 6-10 mins on source exposures.…”

Section: Infrared Flux Uncertainty Estimatesmentioning

confidence: 50%

Inefficient star formation in extremely metal poor galaxies

Shi

Armus

Hélou

et al. 2014

Nature

175

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The first galaxies contain stars born out of gas with little or no metals. The lack of metals is expected to inhibit efficient gas cooling and star formation 1, 2 but this effect has yet to be observed in galaxies with oxygen abundance relative to hydrogen below a tenth of that of the Sun 2-4 . Extremely metal poor nearby galaxies may be our best local laboratories for studying in detail the conditions that prevailed in low metallicity galaxies at early epochs. Carbon Monoxide (CO) emission is unreliable as tracers of gas at low metallicities 5-7 , and while dust has been used to trace gas in lowmetallicity galaxies 5, 8-10 , low-spatial resolution in the far-infrared has typically led to large uncertainties 9, 10 . Here we report spatiallyresolved infrared observations of two galaxies with oxygen abundances below 10 per cent solar, and show that stars form very inefficiently in seven star-forming clumps of these galaxies. The star formation efficiencies are more than ten times lower than found in normal, metal rich galaxies today, suggesting that star formation may have been very inefficient in the early Universe.The two galaxies that are the focus of this study are Sextans A, a dwarf irregular at 1.4 Mpc with oxygen abundance of 7% Solar 11,12 , and ESO 146-G14, a low-surface-brightness galaxy at 22.5 Mpc with 9% solar oxygen abundance 11,13 . Their metallicities may be similar to that of gas out of which Population II stars form in the early Universe around redshift from 7 to 12 14 . An effective way to estimate the total gas content in extremely metal poor galaxies is to employ spatially resolved maps of the far-infrared (IR) emitting dust as tracers of the atomic and molecular gas by multiplying with an appropriate gas-todust ratio (GDR) that is inferred from regions with little or no active star formation, a methodology that has been extensively demonstrated in relatively metal rich galaxies 7, 15 .The infrared observations described in this paper were carried out at 70, 160, 250, 350 and 500 µm with the Photodetector Array Camera and Spectrometer (PACS) 16 and Spectral and Photometric Imaging REceiver (SPIRE) 17 onboard the Herschel Space Observatory. We complement our far-IR data with mid-IR images from the Spitzer Space Telescope to construct the full IR spectral energy distributions (SED). Far-ultraviolet (UV) images from the GALEX Space Telescope archive are used to trace un-obscured star formation. Maps of atomic gas are available in the literature for Sextans A . Figure 1 shows the multi-wavelength images of our sample galaxies. Based on the far-UV image we defined the star-forming disk as an ellipse to closely follow the 10-σ (∼ 26 AB-mag/arcsec 2 ) contour of the far-UV emission as shown in the Fig. 1 gions with elevated (> 3σ) emission relative to local disk backgrounds in both far-UV and 160 µm bands after smoothing images to 28 arcsec resolutions. The diffuse emission is measured by subtracting the total emission of all star-forming clumps in the disk from the integrated disk emission. For Se...

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Section: Infrared Flux Uncertainty Estimatesmentioning

confidence: 50%

Inefficient star formation in extremely metal poor galaxies

Shi

Armus

Hélou

et al. 2014

Nature

175

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“…Abell 2744 was also observed during the Spitzer cryo-mission, with MIPS 24 μm and IRAC 3.6-8 μm observations (PI G. Rieke). This cluster is part of the Herschel Lensing Survey (Egami et al 2010), with deep Herschel Space Observatory PACS 100/160 μm and SPIRE 250/350/500 μm imaging.…”

Section: Abell 2744mentioning

confidence: 99%

“…Selected as a CLASH cluster, the HST imaging revealed a quintuply lensed z∼6 galaxy (Balestra et al 2013;Monna et al 2013). The images from the Herschel Lensing Survey (Egami et al 2010) show an associated 870 μm source, a lensed submillimeter galaxy with one of the highest redshifts known (Boone et al 2013). Abell S1063 is one of the less powerful lensers (Table 2) and the most relaxed of the selected Frontier Fields clusters.…”

Section: Abell S1063mentioning

confidence: 99%

“…It is inaccessible from Maunakea but easily observed by ALMA and the VLT. As an SPT (South Pole Telescope)and CLASH cluster, it had extensive spectroscopic and ancillary data already, including shallow Chandra imaging (PI A. Romer), Herschel (Egami et al 2010; also Open Time Cycle 2 program, PI T. Rawle), SZ, Spitzer cryo-mission MIPS and IRAC (PI G. Rieke), and VLT spectroscopy (e.g., Balestra et al 2013). Recently, Abell S1063 has been targeted by the VLT MUSE integral field spectrograph (Karman et al 2015).…”

Section: Abell S1063mentioning

confidence: 99%

“…This cluster was also observed with the Spitzer cryogenic mission with both IRAC and MIPS (PI D. Kocevski) and the Spitzer warmmission SURFSUP program (PI M. Bradacȇ t al. 2014), as well as with the Herschel Space Observatory (Egami et al 2010). A spectroscopic redshift catalog was recently published by Ebeling et al (2014).…”

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confidence: 99%

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The Frontier Fields: Survey Design and Initial Results

Lotz

Koekemoer

Coe

et al. 2017

ApJ

Self Cite

609

574

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What are the faintest distant galaxies we can see with the Hubble Space Telescope (HST) now, before the launch of the James Webb Space Telescope? This is the challenge taken up by the Frontier Fields, a Director's discretionary time campaign with HST and the Spitzer Space Telescope to see deeper into the universe than ever before. The Frontier Fields combines the power of HST and Spitzer with the natural gravitational telescopes of massive highmagnification clusters of galaxies to produce the deepest observations of clusters and their lensed galaxies ever obtained. Six clusters-Abell 2744, MACSJ0416.1-2403, MACSJ0717.5+3745, MACSJ1149.5+2223, Abell S1063, and Abell 370-have been targeted by the HST ACS/WFC and WFC3/IR cameras with coordinated parallel fields for over 840 HST orbits. The parallel fields are the second-deepest observations thus far by HST with 5σ point-source depths of ∼29th ABmag. Galaxies behind the clusters experience typical magnification factors of a few, with small regions magnified by factors of 10-100. Therefore, the Frontier Field cluster HST images achieve intrinsic depths of ∼30-33 mag over very small volumes. Spitzer has obtained over 1000 hr of Director's discretionary imaging of the Frontier Field cluster and parallels in IRAC 3.6 and 4.5 μm bands to 5σ point-source depths of ∼26.5, 26.0 ABmag. We demonstrate the exceptional sensitivity of the HST Frontier Field images to faint high-redshift galaxies, and review the initial results related to the primary science goals.

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