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Title: A very large ( θ E ≳ 40") strong gravitational lens selected with the Sunyaev–Zel’dovich effect: PLCK G287.0+32.9 ( z = 0.38)

Abstract

Since galaxy clusters sit at the high end of the mass function, the number of galaxy clusters both massive and concentrated enough to yield particularly large Einstein radii poses useful constraints on cosmological and structure formation models. To date, less than a handful of clusters are known to have Einstein radii exceeding $$\sim 40^{\prime\prime} $$ (for a source at $${z}_{s}\simeq 2$$, nominally). Here, we report an addition to that list of the Sunyaev–Zel'dovich (SZ) selected cluster, PLCK G287.0+32.9 (z = 0.38), the second-highest SZ-mass (M 500) cluster from the Planck catalog. We present the first strong-lensing analysis of the cluster, identifying 20 sets of multiply imaged galaxies and candidates in new Hubble Space Telescope ( HST) data, including a long, $$l\sim 22^{\prime\prime} $$ giant arc, as well as a quadruply imaged, apparently bright (magnified to $${J}_{{\rm{F}}110{\rm{W}}}=25.3$$ AB), likely high-redshift dropout galaxy at $${z}_{\mathrm{phot}}=6.90$$ [6.13–8.43] (95% C.I.). Our analysis reveals a very large critical area (1.55 arcmin2, $${z}_{s}\simeq 2$$), corresponding to an effective Einstein radius of $${\theta }_{{\rm{E}}}\sim 42^{\prime\prime} $$. Furthermore, the model suggests the critical area will expand to 2.58 arcmin2 ($${\theta }_{{\rm{E}}}\sim 54^{\prime\prime} $$) for sources at $${z}_{s}\sim 10$$. Our work adds to recent efforts to model very massive clusters toward the launch of the James Webb Space Telescope, in order to identify the most useful cosmic lenses for studying the early universe. Spectroscopic redshifts for the multiply imaged galaxies and additional HST data will be necessary for refining the lens model and verifying the nature of the $$z\sim 7$$ dropout.

Authors:
ORCiD logo [1]; ORCiD logo [2];  [2]; ORCiD logo [3];  [4]; ORCiD logo [5]; ORCiD logo [6]; ORCiD logo [7];  [2];  [8]
  1. Ben-Gurion Univ. of the Negev, Be'er-Sheva (Israel)
  2. Univ. Observatory Munich, Munich (Germany); Max Planck Institute for Extraterrestrial Physics, Garching (Germany)
  3. Space Telescope Science Institute, Baltimore, MD (United States)
  4. INAF - Osservatorio Astronomico di Trieste, Trieste (Italy)
  5. SLAC National Accelerator Lab., Menlo Park, CA (United States); Stanford Univ., Stanford, CA (United States)
  6. Univ. Observatory Munich, Munich (Germany); INAF - Osservatorio Astronomico di Trieste, Trieste (Italy)
  7. INAF - Osservatorio Astronomico di Trieste, Trieste (Italy); Univ. degli Studi di Trieste, Trieste (Italy)
  8. INAF - Osservatorio Astronomico di Capodimonte, Napoli (Italy)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1360219
Grant/Contract Number:
AC02-76SF00515
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
The Astrophysical Journal. Letters
Additional Journal Information:
Journal Volume: 839; Journal Issue: 1; Journal ID: ISSN 2041-8213
Publisher:
Institute of Physics (IOP)
Country of Publication:
United States
Language:
English
Subject:
79 ASTRONOMY AND ASTROPHYSICS; galaxies: clusters: general; galaxies: clusters: individual (PLCK G287.0+32.9); gravitational lensing; strong

Citation Formats

Zitrin, Adi, Seitz, Stella, Monna, Anna, Koekemoer, Anton M., Nonino, Mario, Gruen, Daniel, Balestra, Italo, Girardi, Marisa, Koppenhoefer, Johannes, and Mercurio, Amata. A very large (θE ≳ 40") strong gravitational lens selected with the Sunyaev–Zel’dovich effect: PLCK G287.0+32.9 (z = 0.38). United States: N. p., 2017. Web. doi:10.3847/2041-8213/aa69be.
Zitrin, Adi, Seitz, Stella, Monna, Anna, Koekemoer, Anton M., Nonino, Mario, Gruen, Daniel, Balestra, Italo, Girardi, Marisa, Koppenhoefer, Johannes, & Mercurio, Amata. A very large (θE ≳ 40") strong gravitational lens selected with the Sunyaev–Zel’dovich effect: PLCK G287.0+32.9 (z = 0.38). United States. doi:10.3847/2041-8213/aa69be.
Zitrin, Adi, Seitz, Stella, Monna, Anna, Koekemoer, Anton M., Nonino, Mario, Gruen, Daniel, Balestra, Italo, Girardi, Marisa, Koppenhoefer, Johannes, and Mercurio, Amata. Mon . "A very large (θE ≳ 40") strong gravitational lens selected with the Sunyaev–Zel’dovich effect: PLCK G287.0+32.9 (z = 0.38)". United States. doi:10.3847/2041-8213/aa69be. https://www.osti.gov/servlets/purl/1360219.
@article{osti_1360219,
title = {A very large (θE ≳ 40") strong gravitational lens selected with the Sunyaev–Zel’dovich effect: PLCK G287.0+32.9 (z = 0.38)},
author = {Zitrin, Adi and Seitz, Stella and Monna, Anna and Koekemoer, Anton M. and Nonino, Mario and Gruen, Daniel and Balestra, Italo and Girardi, Marisa and Koppenhoefer, Johannes and Mercurio, Amata},
abstractNote = {Since galaxy clusters sit at the high end of the mass function, the number of galaxy clusters both massive and concentrated enough to yield particularly large Einstein radii poses useful constraints on cosmological and structure formation models. To date, less than a handful of clusters are known to have Einstein radii exceeding $\sim 40^{\prime\prime} $ (for a source at ${z}_{s}\simeq 2$, nominally). Here, we report an addition to that list of the Sunyaev–Zel'dovich (SZ) selected cluster, PLCK G287.0+32.9 (z = 0.38), the second-highest SZ-mass (M 500) cluster from the Planck catalog. We present the first strong-lensing analysis of the cluster, identifying 20 sets of multiply imaged galaxies and candidates in new Hubble Space Telescope (HST) data, including a long, $l\sim 22^{\prime\prime} $ giant arc, as well as a quadruply imaged, apparently bright (magnified to ${J}_{{\rm{F}}110{\rm{W}}}=25.3$ AB), likely high-redshift dropout galaxy at ${z}_{\mathrm{phot}}=6.90$ [6.13–8.43] (95% C.I.). Our analysis reveals a very large critical area (1.55 arcmin2, ${z}_{s}\simeq 2$), corresponding to an effective Einstein radius of ${\theta }_{{\rm{E}}}\sim 42^{\prime\prime} $. Furthermore, the model suggests the critical area will expand to 2.58 arcmin2 (${\theta }_{{\rm{E}}}\sim 54^{\prime\prime} $) for sources at ${z}_{s}\sim 10$. Our work adds to recent efforts to model very massive clusters toward the launch of the James Webb Space Telescope, in order to identify the most useful cosmic lenses for studying the early universe. Spectroscopic redshifts for the multiply imaged galaxies and additional HST data will be necessary for refining the lens model and verifying the nature of the $z\sim 7$ dropout.},
doi = {10.3847/2041-8213/aa69be},
journal = {The Astrophysical Journal. Letters},
number = 1,
volume = 839,
place = {United States},
year = {Mon Apr 10 00:00:00 EDT 2017},
month = {Mon Apr 10 00:00:00 EDT 2017}
}

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  • We report the discovery of large-scale diffuse non-thermal radio emission in PLCK G287.0+32.9, an exceptionally hot (T {approx} 13 keV), massive, and luminous galaxy cluster, strongly detected by the Planck satellite in a recent, all-sky blind search for new clusters through Sunyaev-Zel'dovich effect. Giant Metrewave Radio Telescope 150 MHz and Very Large Array 1.4 GHz radio data reveal a pair of giant (>1 Mpc) 'arc'-shaped peripheral radio relics (signatures of shock waves) of unprecedented scale (linear separation {approx}4.4 Mpc at redshift 0.39), located at distances from the cluster center that are about 0.7 and 1.3 of the cluster's virial radius,more » respectfully. Another possible giant relic and a radio halo is detected closer to the cluster center. These relic sources are unique 'signposts' of extremely energetic mergers and shocks (both ongoing and past) that are assembling and heating up this very massive galaxy cluster. They are also a probe of the filamentary cosmic-web structure beyond the cluster virial radius. Optical imaging with the IUCAA 2 m telescope and XMM-Newton X-ray data confirm a very rich galaxy cluster with a morphologically disturbed core region, suggesting a dynamically perturbed merging system.« less
  • The second most significant detection of the Planck Sunyaev-Zel'dovich survey, PLCK G287.0+32.9 (z = 0.385), boasts two similarly bright radio relics and a radio halo. One radio relic is locatedmore » $$\sim 400\,\mathrm{kpc}$$ NW of the X-ray peak and the other $$\sim 2.8$$ Mpc to the SE. This large difference suggests that a complex merging scenario is required. A key missing puzzle for the merging scenario reconstruction is the underlying dark matter distribution in high resolution. Here, we present a joint Subaru Telescope and Hubble Space Telescope weak-lensing analysis of the cluster. Our analysis shows that the mass distribution features four significant substructures. Of the substructures, a primary cluster of mass $${M}_{200{\rm{c}}}={1.59}_{-0.22}^{+0.25}\times {10}^{15}\ {h}_{70}^{-1}\ {M}_{\odot }$$ dominates the weak-lensing signal. This cluster is likely to be undergoing a merger with one (or more) subcluster whose mass is approximately a factor of 10 lower. One candidate is the subcluster of mass $${M}_{200{\rm{c}}}={1.16}_{-0.13}^{+0.15}\times {10}^{14}\ {h}_{70}^{-1}\ {M}_{\odot }$$ located $$\sim 400\,\mathrm{kpc}$$ to the SE. The location of this subcluster suggests that its interaction with the primary cluster could be the source of the NW radio relic. Another subcluster is detected $$\sim 2$$ Mpc to the SE of the X-ray peak with mass $${M}_{200{\rm{c}}}={1.68}_{-0.20}^{+0.22}\times {10}^{14}\ {h}_{70}^{-1}\ {M}_{\odot }$$. This SE subcluster is in the vicinity of the SE radio relic and may have created the SE radio relic during a past merger with the primary cluster. The fourth subcluster, $${M}_{200{\rm{c}}}={1.87}_{-0.22}^{+0.24}\times {10}^{14}\ {h}_{70}^{-1}\ {M}_{\odot }$$, is NW of the X-ray peak and beyond the NW radio relic.« less
  • Strong gravitational lenses are now being routinely discovered in wide-field surveys at (sub-)millimeter wavelengths. We present Submillimeter Array (SMA) high-spatial resolution imaging and Gemini-South and Multiple Mirror Telescope optical spectroscopy of strong lens candidates discovered in the two widest extragalactic surveys conducted by the Herschel Space Observatory: the Herschel-Astrophysical Terahertz Large Area Survey (H-ATLAS) and the Herschel Multi-tiered Extragalactic Survey (HerMES). From a sample of 30 Herschel sources with S {sub 500} > 100 mJy, 21 are strongly lensed (i.e., multiply imaged), 4 are moderately lensed (i.e., singly imaged), and the remainder require additional data to determine their lensing status.more » We apply a visibility-plane lens modeling technique to the SMA data to recover information about the masses of the lenses as well as the intrinsic (i.e., unlensed) sizes (r {sub half}) and far-infrared luminosities (L {sub FIR}) of the lensed submillimeter galaxies (SMGs). The sample of lenses comprises primarily isolated massive galaxies, but includes some groups and clusters as well. Several of the lenses are located at z {sub lens} > 0.7, a redshift regime that is inaccessible to lens searches based on Sloan Digital Sky Survey spectroscopy. The lensed SMGs are amplified by factors that are significantly below statistical model predictions given the 500 μm flux densities of our sample. We speculate that this may reflect a deficiency in our understanding of the intrinsic sizes and luminosities of the brightest SMGs. The lensed SMGs span nearly one decade in L {sub FIR} (median L {sub FIR} = 7.9 × 10{sup 12} L {sub ☉}) and two decades in FIR luminosity surface density (median Σ{sub FIR} = 6.0 × 10{sup 11} L {sub ☉} kpc{sup –2}). The strong lenses in this sample and others identified via (sub-)mm surveys will provide a wealth of information regarding the astrophysics of galaxy formation and evolution over a wide range in redshift.« less
  • Here, we report the Fermi Large Area Telescope (LAT) detection of two very-high-energy (VHE, E > 100 GeV) γ-ray photons from the directional vicinity of the distant (redshift, z = 1.1) blazar PKS 0426–380. The null hypothesis that both the 134 and 122 GeV photons originate from unrelated sources can be rejected at the 5.5σ confidence level. We therefore claim that at least one of the two VHE photons is securely associated with PKS 0426–380, making it the most distant VHE emitter known to date. The results are in agreement with recent Fermi-LAT constraints on the extragalactic background light (EBL)more » intensity, which imply a z sime 1 horizon for sime 100 GeV photons. The LAT detection of the two VHE γ-rays coincided roughly with flaring states of the source, although we did not find an exact correspondence between the VHE photon arrival times and the flux maxima at lower γ-ray energies. Modeling the γ-ray continuum of PKS 0426–380 with daily bins revealed a significant spectral hardening around the time of the first VHE event detection (LAT photon index Γ sime 1.4) but on the other hand no pronounced spectral changes near the detection time of the second one. This combination implies a rather complex variability pattern of the source in γ-rays during the flaring epochs. An additional flat component is possibly present above several tens of GeV in the EBL-corrected Fermi-LAT spectrum accumulated over the ~8 month high state.« less