J/ApJ/948/93 HST/WFC3 phot. of the S1-SX images of SN Refsdal (Kelly+, 2023)
The magnificent five images of supernova Refsdal: time delay and magnification
measurements.
Kelly P.L., Rodney S., Treu T., Birrer S., Bonvin V., Dessart L.,
Foley R.J., Filippenko A.V., Gilman D., Jha S., Hjorth J., Mandel K.,
Millon M., Pierel J., Thorp S., Zitrin A., Broadhurst T., Chen W.,
Diego J.M., Dressler A., Graur Or, Jauzac M., Malkan M.A., McCully C.,
Oguri M., Postman M., Schmidt K.B., Sharon K., Tucker B.E.,
von der Linden A., Wambsganss J.
<Astrophys. J., 948, 93 (2023)>
=2023ApJ...948...93K 2023ApJ...948...93K
ADC_Keywords: Photometry, HST; Supernovae; Gravitational lensing; Infrared
Keywords: Hubble constant ; Gravitational lensing ; Type II supernovae ;
Cosmology
Abstract:
In late 2014, four images of supernova (SN) "Refsdal," the first known
example of a strongly lensed SN with multiple resolved images, were
detected in the MACS J1149 galaxy-cluster field. Following the images'
discovery, the SN was predicted to reappear within hundreds of days at
a new position ∼8" away in the field. The observed reappearance in
late 2015 makes it possible to carry out Refsdal's original proposal
to use a multiply imaged SN to measure the Hubble constant H0, since
the time delay between appearances should vary inversely with H0.
Moreover, the position, brightness, and timing of the reappearance
enable a novel test of the blind predictions of galaxy-cluster models,
which are typically constrained only by the positions of multiply
imaged galaxies. We have developed a new photometry pipeline that uses
DOLPHOT to measure the fluxes of the five images of SN Refsdal from
difference images. We apply four separate techniques to perform a
blind measurement of the relative time delays and magnification ratios
between the last image SX and the earlier images S1-S4. We measure the
relative time delay of SX-S1 to be 376.0-5.5+5.6days and the
relative magnification to be 0.30-0.3+0.5. This corresponds to a
1.5% precision on the time delay and 17% precision for the
magnification ratios and includes uncertainties due to millilensing
and microlensing. In an accompanying paper, we place initial and blind
constraints on the value of the Hubble constant.
Description:
Following the discovery of the four images S1-S4 of SN Refsdal in
GLASS imaging (Kelly+ 2015Sci...347.1123K 2015Sci...347.1123K), the Hubble Frontier Fields
(HFF) program (DD-13504; PI Lotz) fortuitously began its
already-scheduled imaging campaign of the MACS J1149 galaxy-cluster
field. To complement the early HFF imaging, we acquired additional
imaging as part of the FrontierSN program (GO-13386; PI Rodney).
We obtained 30 orbits of HST WFC3 IR G141 grism spectroscopy to
classify spectroscopically the SN before it reached maximum brightness
as part of a Director's Discretionary Time program (DD-14041;
PI Kelly; Kelly+ 2016ApJ...831..205K 2016ApJ...831..205K).
To detect the reappearance of SN Refsdal in image SX, as shown in
Figure 1, and measure its time delay and magnification relative to
S1-S4, we executed a multicycle "Refsdal Redux" monitoring campaign
(GO-14199; PI Kelly). This program continued to monitor the MACS J1149
field at a cadence of approximately every 2 weeks whenever the field
was visible to HST (from approximately late October through July).
In 2016 May these observations captured a microlensing peak of a
highly magnified blue supergiant star (nicknamed Icarus) in
SN Refsdal's host galaxy (Kelly+ 2018NatAs...2..334K 2018NatAs...2..334K). This prompted
additional HST follow-up observations of the MACS J1149 field
(DD-14528; DD-14872; PI Kelly).
See Section 2.
Objects:
----------------------------------------------------------
RA (ICRS) DE Designation(s)
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11 49 36.00 +22 23 48.1 SN Refsdal = NAME SN Refsdal
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
images.dat 57 5 J2000 positions of the five detected images of
SN Refsdal (Table 2) and lensing parameters (Table 6)
table3.dat 73 805 Photometry of SN Refsdal
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See also:
B/hst : HST Archived Exposures Catalog (STScI, 2007)
J/ApJS/199/25 : CLASH sources for MACS1149.6+2223 (Postman+, 2012)
J/ApJ/812/114 : Grism Lens-Amplified Survey from Space. I. (Treu+, 2015)
J/ApJ/822/78 : VLT/MUSE sp. obs. of MACS J1149.5+2223 (Grillo+, 2016)
J/ApJ/819/114 : Strong lensing mass modeling of HFF clusters (Kawamata+, 2016)
J/ApJ/817/60 : Multiply imaged supernova Refsdal (Treu+, 2016)
J/A+A/642/A193 : Rc-band light curves of 6 lensed QSOs (Millon+, 2020)
J/A+A/640/A105 : R-band light curves of 23 lensed QSOs (Millon+, 2020)
Byte-by-byte Description of file: images.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Obj Image of SN Refsdal name
4- 5 I2 h RAh Hour of right ascension (J2000)
7- 8 I2 min RAm Minute of right ascension (J2000)
10- 15 F6.3 s RAs Second of right ascension (J2000)
17 A1 --- DE- Sign of declination (J2000)
18- 19 I2 deg DEd Degree of declination (J2000)
21- 22 I2 arcmin DEm Arcminute of declination (J2000)
24- 28 F5.2 arcsec DEs Arcsecond of declination (J2000)
30- 34 F5.3 --- K [0.67/0.97] Convergence, Κ parameter (1)
36- 40 F5.3 --- gamma [0.09/0.5] Shear, γ parameter (1)
42- 45 F4.1 --- mu [4.2/19] Magnification, µ parameter (1)
47 A1 --- Parity Parity (1)
49- 53 F5.1 --- mut [-10.6/10.5] µt parameter (1)
55- 57 F3.1 --- mur [1.4/2.7] µr parameter (1)
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Note (1): We measure these parameters from the v3 GLAFIC maps posted online at
https://archive.stsci.edu/pub/hlsp/frontier/macs1149/models/glafic/v3/
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Obj Image of SN Refsdal
4- 8 A5 --- Filt WFC3-IR Filter (F105W, F125W or F160W)
10- 27 F18.12 d MJD [56598.13/57756.91] Modified Julian date (1)
29- 51 F23.20 uJy Flux [-0.06/0.8] Flux in Filt
53- 73 F21.19 uJy e_Flux [0/0.7] Uncertainty in Flux
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Note (1): Modified Julian Date (JD-2400000.5) at the beginning of the
observation.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Emmanuelle Perret [CDS] 25-Apr-2025