2016/06/30 by Masayuki Tanaka, Kenneth Wong, Kenneth C. Wong +13
Engineering · Physics and Astronomy · #Astronomy and Astrophysical Research #Fundamental plane (elliptical galaxies) #Galaxies: Formation, Evolution, Phenomena #Galaxy #Lens (geology) #Offset (computer science) #Redshift #Ring (chemistry) #Space Technology and Applications #astro-ph.CO #astro-ph.GA
paper · pdf · doi:10.3847/2041-8205/826/2/l19
6 pages, 3 figures, accepted for publication in ApJL
arxiv created 2016/06/30 · openalex created_date 2016/07/22 · openalex publication_date 2016/07/25 · arxiv updated 2016/08/03 · openalex updated_date 2026/08/05
ABSTRACT We report the serendipitous discovery of HSC J142449−005322, a double source plane lens system in the Hyper Suprime-Cam Subaru Strategic Program. We dub the system Eye of Horus . The lens galaxy is a very massive early-type galaxy with stellar mass of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mo>∼</mml:mo> <mml:mn>7</mml:mn> <mml:mo>×</mml:mo> <mml:msup> <mml:mrow> <mml:mn>10</mml:mn> </mml:mrow> <mml:mrow> <mml:mn>11</mml:mn> </mml:mrow> </mml:msup> <mml:mspace width="0.25em"/> <mml:msub> <mml:mrow> <mml:mi>M</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>⊙</mml:mo> </mml:mrow> </mml:msub> </mml:math> located at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>z</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">L</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>0.795</mml:mn> </mml:math> . The system exhibits two arcs/rings with clearly different colors, including several knots. We have performed spectroscopic follow-up observations of the system with FIRE on Magellan . The outer ring is confirmed at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>z</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">S</mml:mi> <mml:mn>2</mml:mn> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>1.988</mml:mn> </mml:math> with multiple emission lines, while the inner arc and counterimage is confirmed at <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msub> <mml:mrow> <mml:mi>z</mml:mi> </mml:mrow> <mml:mrow> <mml:mi mathvariant="normal">S</mml:mi> <mml:mn>1</mml:mn> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>1.302</mml:mn> </mml:math> . This makes it the first double source plane system with spectroscopic redshifts of both sources. Interestingly, redshifts of two of the knots embedded in the outer ring are found to be offset by <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:mi mathvariant="normal">Δ</mml:mi> <mml:mi>z</mml:mi> <mml:mo>=</mml:mo> <mml:mn>0.002</mml:mn> </mml:math> from the other knots, suggesting that the outer ring consists of at least two distinct components in the source plane. We perform lens modeling with two independent codes and successfully reproduce the main features of the system. However, two of the lensed sources separated by ∼0.7 arcsec cannot be reproduced by a smooth potential, and the addition of substructure to the lens potential is required to reproduce them. Higher-resolution imaging of the system will help decipher the origin of this lensing feature and potentially detect the substructure.