Constraints on the Progenitor System of the Type Ia Supernova 2014J from Pre-Explosion Hubble Space Telescope Imaging
Patrick L. Kelly, Ori D. Fox, Alexei V. Filippenko, S. Bradley Cenko, Lisa Prato, Gail Schaefer, Ken J. Shen, WeiKang Zheng, Melissa L. Graham, Brad E. Tucker
SSubmitted to The Astrophysical Journal
Preprint typeset using L A TEX style emulateapj v. 5/2/11
CONSTRAINTS ON THE PROGENITOR SYSTEM OF THE TYPE IA SUPERNOVA 2014J FROMPRE-EXPLOSION
HUBBLE SPACE TELESCOPE
IMAGING
Patrick L. Kelly , Ori D. Fox , Alexei V. Filippenko , S. Bradley Cenko , Lisa Prato , Gail Schaefer , Ken J.Shen , WeiKang Zheng , Melissa L. Graham , and Brad E. Tucker Submitted to The Astrophysical Journal
ABSTRACTWe constrain the properties of the progenitor system of the highly reddened Type Ia supernova(SN) 2014J in Messier 82 (M82; d ≈ . K -bandadaptive optics images, and we find no evidence for flux from a progenitor system in pre-explosionnear-ultraviolet through near-infrared Hubble Space Telescope (HST) images. Our upper limits excludesystems having a bright red giant companion, including symbiotic novae with luminosities comparableto that of RS Ophiuchi. While the flux constraints are also inconsistent with predictions for compar-atively cool He-donor systems ( T (cid:46) R V and A V values, but significantlygreater values than those inferred from the SN light curve and spectrum would yield proportionallybrighter luminosity limits. The comparatively faint flux expected from a binary progenitor systemconsisting of white dwarf stars would not have been detected in the pre-explosion HST imaging. In-frared
HST exposures yield more stringent constraints on the luminosities of very cool (
T <
Subject headings: supernovae: general – supernovae: individual (SN 2014J) – binaries: symbiotic INTRODUCTION
The exceptional luminosity of Type Ia supernovae(SN Ia), and the tight empirical relationships among thedecline rate, color, and peak luminosity of their lightcurves (Phillips 1993; Riess et al. 1996), make SN Ia use-ful probes of the cosmic expansion history (Riess et al.1998; Perlmutter et al. 1999). SN Ia spectra and inferred Ni masses (e.g., Mazzali et al. 2007) show reasonableagreement with models of the thermonuclear explosionsof carbon-oxygen white dwarfs (Hillebrandt & Niemeyer2000; Kasen & Plewa 2005; Kasen & Woosley 2007;Kasen et al. 2009). Additional evidence for a compara-tively old progenitor population comes from the presenceof SN Ia in passive galaxies, and the observation thatthey show no preference for the brightest regions of theirhosts, in contrast to core-collapse explosions that also ex-hibit H- and He-deficient spectra (Kelly et al. 2008; seealso Raskin et al. 2009).For sufficiently nearby SN Ia ( d (cid:46)
10 Mpc), pre-explosion
HST imaging has the sensitivity to detect sev-eral classes of candidate progenitor systems. Currentconstraints suggest that SN Ia progenitor systems consistprimarily of either binary white dwarfs (Iben & Tutukov1984; Webbink 1984; Shen & Bildsten 2014), or binarieswhere a single white dwarf accretes matter from a stellar [email protected] Department of Astronomy, University of California, Berke-ley, CA 94720-3411, USA NASA/Goddard Space Flight Center, Code 662, Greenbelt,MD 20771, USA Lowell Observatory, 1400 West Mars Hill Road, Flagstaff,AZ 86001, USA The CHARA Array of Georgia State University, Mount Wil-son Observatory, Mount Wilson, CA, 91023, USA Einstein Fellow Research School of Astronomy and Astrophysics, The Aus-tralian National University, Weston Creek, ACT 2611, Australia companion (Whelan & Iben 1973; Han & Podsiadlowski2004). For the latter, single-degenerate channel, thewhite dwarf gains matter from a companion star up to apoint where its mass is close to the Chandrasekhar limit(1.4 M (cid:12) ), precipitating eventual thermonuclear runaway.Accretion onto a white dwarf primary can occur throughRoche-lobe overflow (RLOF) from a secondary with a Henvelope (van den Heuvel et al. 1992) or from a He star(Nomoto 1982; Yoon & Langer 2003; Wang et al. 2009;Liu et al. 2010; Geier et al. 2013). Alternatively, in thecase of the symbiotic channel, the white dwarf accretesmass from the wind generated by the secondary (Munari& Renzini 1992; Patat et al. 2011). Characterizing thediversity of SN Ia progenitor systems may be useful forexplaining evidence that the luminosities of SN Ia havea ∼ . d ≈ . HST imaging of the explo-sion site whose coordinates we measure using Keck-IIadaptive optics (AO) imaging. Section 2 provides a briefsummary of the discovery and early analysis of the spec-tra and light curve of SN 2014J. In §
3, we describe the a r X i v : . [ a s t r o - ph . GA ] J un Keck AO and
HST pre-explosion images that we analyzein this paper. The methods we use to extract upper lu-minosity limits for the progenitor system are explained in §
4, while § DISCOVERY AND EARLY ANALYSIS OF SN 2014J
SN 2014J was discovered by Fossey et al. (2014) on 21January 2014 (UT dates are used throughout this paper)during a University College London class observing ses-sion. Zheng et al. (2014) found that the light curve favorsa time of first light of January 14.75 ( ± t dependence.Tendulkar et al. (2014; also Goobar et al. 2014) ac-quired K -band images with the Near Infrared Camera 2(NIRC2) in conjunction with the adaptive optics (AO)system (Wizinowich et al. 2006) on the Keck-II 10-mtelescope. The corrected point-spread function (PSF) oftheir coadded image had a full width at half-maximumintensity (FWHM) of 0.36 (cid:48)(cid:48) (measured at a 10 (cid:48)(cid:48) offsetfrom SN 2014J). Goobar et al. (2014) consider a source0.2 (cid:48)(cid:48) (5 σ ) from the measured SN position as a potentialcompanion, although they suggest that a radio upperlimit (Chandler & Marvil 2014) disfavors this possibilityby setting a prohibitively low constraint on a donor star’smass-loss rate.After removing E ( B − V ) MW = 0 .
14 mag Galacticreddening determined by Schlafly & Finkbeiner (2011),Goobar et al. (2014) find that the shape of the opti-cal SN 2014J spectrum may be reproduced by applyinga low R V = A V /E ( B − V ) extinction curve to a spec-trum of SN 2011fe, a spectroscopically normal and unred-dened SN Ia; a Cardelli et al. (1989) reddening law with E ( B − V ) SN = 1 . ± .
05 mag and R V = 1 . ± .
15 pro-vides the best match to the observed SN 2014J spectrum.The favored value of A V is consistent with the measuredequivalent width (EW) of the diffuse interstellar band(DIB) at 5780 ˚A.Nielsen et al. (2014) analyze archival observationstaken with the Chandra
X-ray telescope of the posi-tion of SN 2014J. They are not able to exclude a low-temperature ( kT eff (cid:46)
80 eV) supersoft X-ray source co-incident with the explosion. Additionally, they find thatthe explosion coordinates lie near the center of a ∼
200 pcstructure of diffuse X-ray emission with inferred mass ∼ × M (cid:12) , which they suggest may be a bubble in-flated by one or more previous SN. Nielsen et al. (2014)consider the possibility that SN 2014J may be associ-ated with a prompt channel linked to nearby recent starformation. DATA
Keck-II NIRC2 Adaptive Optics Imaging
To locate the SN site in pre-explosion
HST exposureswith high precision, we acquired wide-field NIRC2 K -band AO images of the site of SN 2014J on 25 January2014. The SN was used as the guide star to measure tip-tilt corrections. The FWHM natural seeing produced aPSF with 0.65 (cid:48)(cid:48) FWHM, while the AO-corrected imageshave a PSF FWHM of 0.1 (cid:48)(cid:48) near the SN position. We first subtracted the median of a stack of bias ex-posures and then applied flat-field and distortion cor-rections to the NIRC2 images. Although exposures ofSN 2014J were acquired for the minimum possible inte-gration time, the number of counts registered by the sev-eral pixels closest to the peak of the PSF exceeded therange within which the detector has a linear response.Both to register the 18 AO exposures and then to mea-sure the coordinates of the PSF of SN 2014J, we neededto determine the center of the PSF of the SN. We there-fore fit a two-dimensional Gaussian model to the SN pixelintensity distribution in each of the 18 exposures and al-lowed the PSF center coordinates, FWHM, and normal-ization to vary.Saturated pixels in the NIRC2 detector assume lowdata number (DN) values during readout. For eachexposure, we identified (through visual inspection) andmasked the one or two pixels whose low DN values wereconsistent with a saturated pixel. Our χ goodness-of-fitstatistic excludes pixels where the model value was in ex-cess of the nonlinearity threshold. Centers of the fittedGaussian models coincided with the positions of the mostsaturated pixel. The NIRC2 exposures show no evidencefor bleeding from saturated pixels.We then used the best-fitting SN coordinates to alignthe reduced images. The positions of the intensitypeaks of many sources in M82 show variation with wave-length; thus, to mitigate the contribution of this as-trometric noise and to maximize the number of com-mon sources, we registered the coadded K -band imageagainst archival HST
F160W ( H ) images. To minimizethe effect of any remaining astrometric distortion in theNIRC2 coadded image, we used sources only within thecentral 16 (cid:48)(cid:48) × (cid:48)(cid:48) section of the NIRC2 coadded imagewhen cross-registering with the HST
F160W image. Af-ter extracting sources with SExtractor (Bertin & Arnouts1996) and excluding extended objects with r > tweakreg routine in the astrodrizzle package to fit for an astrometric solution from 68 com-mon objects.Figure 1 shows the astrometrically matched, coadded K -band exposure obtained with the NIRC2 AO system,along with the coadded HST
F160W image. The positionof the SN is α = 9 h m s , δ = +69 ◦ (cid:48) (cid:48)(cid:48) (J2000.0) in the World Coordinate System (WCS) of thedrizzled F160W image available from the Hubble LegacyArchive (HLA) . The RMS of the offsets between pairsof matched objects after applying the astrometric solu-tion is 0.057 (cid:48)(cid:48) in RA and 0.055 (cid:48)(cid:48) in Dec. Pre-Explosion HST Imaging
Table 1 provides a list of the
HST imaging datasets ofthe explosion site that we use to place limits on the fluxof the progenitor. Except for the Advanced Camera forSurveys (ACS) exposures, the images within each datasetwere processed, drizzled, and coadded to a common pixelgrid by the HLA team. The ACS coadded mosaics ofdrizzled images that we analyze are High Level ScienceProducts (HLSP) made available by the observers who http://drizzlepac.stsci.edu/ hst 11360 r9 wfc3 ir f160w drz.fits http://hla.stsci.edu/ Figure 1.
Coadded Keck-II K -band NIRC2 AO (left) and HST pre-explosion F160W (right) exposures of the location of SN 2014J. We useonly the central 16 (cid:48)(cid:48) × (cid:48)(cid:48) of the distortion-corrected AO image to perform astrometric registration. The 68 sources used for registrationare identified with white circles, while the position of SN 2014J is marked by a black circle with radius corresponding to the uncertainty inthat position estimate. acquired the data (Proposal 10776; PI: M. Mountain). METHODS
We find an astrometric solution that aligns each coad-ded, drizzled
HST image (see Table 1) with the F160Wreference coadded image through a sequence of two steps.The objective is to achieve an accurate astrometric solu-tion near the coordinates of SN 2014J, so we trim each
HST image to a 30 (cid:48)(cid:48) × (cid:48)(cid:48) subsection centered on theSN position. In the first step, we use the IRAF ccmap routine to compute an approximate astrometric align-ment using ∼ ∼ tweakreg routine in the astrodrizzle package.In Figure 2, we show our measured SN coordinates, aswell as those obtained by Tendulkar et al. (2014), in acoadded image of all pre-explosion HST exposures, andthe F435W (Johnson B ), F814W (Wide I ), and F160W( H ) HST coadded images. The Tendulkar et al. (2014)position was reported relative to the WCS of the HLAF814W image, and we use our astrometric registrationof the images to determine the location of the Tendulkaret al. (2014) position in our reference F160W image. TheSN 2014J position that we measure is offset by 0.08 (cid:48)(cid:48) fromthe coordinates we calculate for the Tendulkar et al.(2014) F814W position in the F160W image.The angular distance between the position we esti-mate and the preliminary coordinates reported by Ten-dulkar et al. (2014) may arise from several differencesbetween our AO coadded images and astrometric fitting.These include the substantially improved resolution of http://iraf.noao.edu/ our NIRC2 AO exposures (0.1 (cid:48)(cid:48) ) compared to those an-alyzed by Tendulkar et al. (2014; 0.36 (cid:48)(cid:48) ), our restrictionof cross-matched sources to those inside of the central16 (cid:48)(cid:48) × (cid:48)(cid:48) region of the 40 (cid:48)(cid:48) × (cid:48)(cid:48) wide-field NIRC2camera to minimize the effects of residual distortion, thenumbers of matched sources (68 and 8, respectively) in-corporated into the astrometric fit by the two analyses,and our matching of sources in the K -band NIRC2 im-age against the near-IR HST
F160W image as opposed tothe I -band F814W image to be able to minimize sourceconfusion and the effects of differential reddening. Upper Flux Limits
As may be seen in the representative images in Fig-ure 2, the local environment of SN 2014J exhibits strongsurface brightness variations from both resolved and un-resolved sources, as well as strong and varying extinc-tion by dust. As in Maoz & Mannucci (2008), our ap-proach for estimating nondetection limits is to add ar-tificial point sources. We create a sequence of images,each with a superimposed artificial point source havingFWHM appropriate to the
HST instrument and band-pass filter. We create a pixelated Gaussian PSF and usethe PyFITS package to add the artificial source to the HST image. We place the PSF ∼ Figure 2.
AO position of SN 2014J in a coadded image of all pre-explosion
HST exposures, as well as in coadded F435W, F814W,and F160W
HST images. The center of the solid white circle shows the position that we measure from our AO data, while the centerof the dashed yellow circle corresponds to the position published by Tendulkar et al. (2014; also Goobar et al. 2014) from separate AOobservations. The root-mean square (RMS) scatter of the astrometric fit between our NIRC2 AO image and the HLA F160W image is0.057 (cid:48)(cid:48) in RA and 0.055 (cid:48)(cid:48) in Dec, and that reported by Tendulkar et al. (2014) relative to the HLA F814W image is 0.023 (cid:48)(cid:48) in RA and0.042 (cid:48)(cid:48) in Dec. The radii of the circles shown in each image correspond to the positional uncertainty of the SN in either the F160W orF814W image, respectively, convolved when appropriate with the RMS astrometric scatter between images in different bands (e.g., F160Wand F435W). Our position is farther from a source considered as a possible progenitor candidate by Goobar et al. (2014) and is coincidentwith a region having strong extinction from dust. identifying the first image for which the brightest pixelof the injected source has more counts than the neigh-boring local maxima produced by photon shot noise andbackground variation, and where pixels adjacent to thepeak of the injected source have elevated counts consis-tent with a PSF.To estimate the statistical significance of these visualdetections for use in likelihood computations, we com-pute detection limits using a complementary technique.We calculate the RMS of the background flux in a regionwithout detected sources or a strong intensity gradient.We consider a 3 σ detection to be one for which the sourceflux exceeds the background RMS inside a 6-pixel aper-ture by a factor of 3.A circular aperture enclosing 80% of the flux of a point source is the default choice for most HST instru-ments when computing the signal-to-noise ratio (S/N) ofa flux measurement using the Exposure Time Calculator(ETC) . For the ACS Wide Field Camera (WFC), thiscorresponds to an area that includes ∼
44 pixels (andcorresponding background noise), and yields a limitingmagnitude that is ∼ . HST images calculated by Li et al. (2011) in their analy-sis of the explosion site of SN 2011fe are consistent with http://etc.stsci.edu/etc/ log[ ν / Hz] l o g [ L ν / ( J y m )] BVRIJHK σ combined limitRushton et al. 2010Zamanov et al. 20102MASS; Darnley et al. 2012Evans et al. 1988Skopal et al. 2014RS Oph model d=1.4 kpcd=1.6 kpcd=3.1 kpc R S O p h Figure 3.
Constraints on the luminosity L ν of the progenitor system against the central frequency ν of the bandpass filter. Values for theGalactic symbiotic nova RS Oph, a candidate single-degenerate progenitor system, in the quiescent phase are plotted for comparison. Foreach HST imaging dataset, the arrow tip marks the estimated 1 σ upper luminosity limit, while the horizontal hatch marks along the arrowshow the 2 σ and 3 σ upper limits. The thick blue line shows the conservative values we adopt as a model for the luminosity of RS Ophin the quiescent phase (with d = 1 . L ν for the range of possible distances to RS Oph(1 . ≤ d ≤ . σ limits inferred from HST observations in all bandpasses using the model SED forRS Oph. The progenitor luminosity limits shown are computed using the extinction and reddening ( R M82 V = 1 . A M82 V = 1 . BVRI andBessell
JHK filters for reference. Measurements of RS Oph from Evans et al. (1988), Rushton et al. (2010), Zamanov et al. (2010), Darnleyet al. (2012), and Skopal (2014) are converted to L ν for d = 1 . estimates instead made using a circular aperture enclos-ing 80% of the flux.As shown in Table 1, the visual magnitude limits arecomparable to the 3 σ limits estimated using the back-ground statistics. We assign accordingly a 3 σ signifi-cance to the visual limits for the purpose of computinglikelihood functions. Constraints on Progenitor Systems
To convert these limits on the apparent magnitudes ofa progenitor system to constraints on a stellar source,we use the Pickles (1998) library to model the spectralenergy distributions (SEDs) of candidate progenitor sys-tems of the SN, as well as (following Li et al. 2011) black- body spectra with temperatures of 35,000, 65,000, and95,000 K. For each combination of
HST filter and instru-ment in Table 1 and all spectroscopic templates, we com-pute synthetic magnitudes with and without extinctionfrom dust. After removing E ( B − V ) MW = 0 .
14 mag offoreground Milky Way ( R V = 3 .
1) extinction, Goo-bar et al. (2014) estimated that additional extinction of E ( B − V ) SN = 1 . ± .
05 mag with R V = 1 . ± .
15 canbest reproduce the shape of a premaximum optical spec-trum of SN 2014J. While we adopt the Goobar et al.(2014) extinction curve for our progenitor constraints, weadditionally compute synthetic magnitudes instead withan R V = 3 . A V favored O5 B5 A5 G0 M542024 M V ( m ag ) Temperature (K) M fl M fl M fl M fl M fl M fl T C r b SN 2006dd limit R S O p h U ScoSN 2011fe limit SN 2014J limitV445 Pup H e li u m s t a r c h a nn e l R e d G i a n t s Figure 4.
Constraints on the position of the SN 2014J progenitor system in the Hertzsprung-Russell (H-R) diagram. The thick brightred line corresponds to the 2 σ M V limits ( R M82 V = 1 . A M82 V = 1 . HST bands. The middle solid gray line shows the 2 σ limits onthe progenitor absolute magnitude obtained using the most constraining single observation, while the upper and lower adjacent gray linesprovide an estimate of the uncertainty on this limit. The region brighter than the most constraining single observation limit is shadedin yellow. Starburst regions of M82 have approximately solar metallicity (F¨orster Schreiber et al. 2001), and we plot stellar evolutionarytracks off of the main sequence (solid black line) calculated by Lejeune & Schaerer (2001) with appropriate abundance ( Z = 0 . σ M V limits for R M82 V = 3 . A M82 V = 1 . R M82 V = 2 mag and A M82 V = 2 . . ± .
02 mag (Jacobs et al. 2009). by Goobar et al. (2014). As we demonstrate in §
5, weobtain similar progenitor constraints for these differingvalues of R V .Following Li et al. (2011), we first translate the up-per limit on the flux for each filtered observation to a2 σ upper limit on the absolute magnitude M V , using adistance modulus to M82 of 27 . ± .
02 mag (Jacobset al. 2009). After repeating this for all observations, weidentify the most constraining upper limit on M V , andrefer to this as the 2 σ “1-frame” limit for each spectrum template. A combined constraint is estimated next byconstructing a probability function that incorporates theupper magnitude limits in all filters. The total probabil-ity (as a function of M V and the template spectrum) isthe product of the probabilities of each filtered observa-tion computed from the predicted model magnitude andthe measured upper magnitude limit.To calculate the combined progenitor system limit, weincrementally increase the absolute brightness M V un-til a 2 σ probability ( p = 0 . ∼ . σ source in a least one HST bandpass image, and in the coadded image in Figure 2.Table 1 shows the detection upper limits for the coad-ded image of each dataset, and Table 2 lists the cor-responding constraint on M J , in addition to M V , com-puted for each Pickles (1998) and blackbody spectrum.For each spectrum, the photometric band providing thefaintest individual absolute magnitude limit is also iden-tified in Table 2.In Figure 3, we plot the limits on the progenitor fluxwe estimate using the HST imaging. We also show mea-surements of the luminosity L ν of RS Oph during itsquiescent phase as a function of frequency ν , and the un-certainty arising from current constraints on its distance. RS Oph SED Model
The luminosity of RS Oph is comparable to our upperdetection limit ( R M82 V = 1 . A M82 V = 1 . J -, H -, and K -band mag-nitudes of RS Oph obtained during quiescence from 1971through 1982 by Swings & Allen (1972), Feast & Glass(1974), Szkody (1977), Sherrington & Jameson (1983),and Kenyon & Gallagher (1983). These measurementsshow modest variation of ± J ≈ . H ≈ . K ≈ .
62 mag) asrepresentative values during the quiescent phase. Mag-nitudes of RS Oph measured by 2MASS (Skrutskie et al.2006) in 1999 ( J = 7 . ± . H = 6 . ± . K = 6 . ± .
01 mag; see also Darnley et al. 2012), as wellas values synthesized from a near-IR spectrum (Rushtonet al. 2010; Skopal 2014), are consistent with the mag-nitudes in quiescence assembled by Evans et al. (1988).We use the optical
BVRI photometry of RS Oph duringquiescence measured by Skopal (2014) to construct ourmodel. The Skopal (2014) optical measurements are, onaverage, fainter than those presented by Zamanov et al.(2010) for several epochs. While Schaefer (2010) com-bine optical and IR colors of RS Oph taken on two datesto infer a possibly fainter flux in the IR, the combinedvalues they present do not appear to be representative ofthe system in quiescence.To estimate the luminosity of RS Oph, we use E ( B − V ) = 0 .
73 mag (Snijders 1987), which is consistent withthe value derived by Anupama & Miko(cid:32)lajewska (1999), for an R V = 3 . ∼ . ∼ . ∼ . V -band total magnitude of 11.5 in quiescence,we estimate a range in absolute magnitude of − . ≤ M V ≤ − .
22 for distances of 1.4 kpc to 3.1 kpc. Usingour decomposition of the spectrum of RS Oph in quies-cence, we estimate that the giant star should be ∼ . V than the total magnitude of the binarysystem. RESULTS
Progenitor Surroundings
As can be seen in Figure 2, the SN 2014J coordinatesthat the AO analysis favors are at a greater angular dis-tance from the nearest resolved point source than theTendulkar et al. (2014) position. This suggests that thestar at a smallest angular offset is not a mass donor tothe white dwarf progenitor of SN 2014J. Our coordinatesalso position SN 2014J closer to the center of an appar-ent dust cloud whose silhouette is visible in optical
HST images.
Progenitor Models
Figure 4 shows the derived constraints on the positionof the progenitor system of SN 2014J in the Hertzsprung-Russell (H-R) diagram. The upper luminosity limit ex-cludes the bright extent of the region, marked in pale red,occupied by red giant stars. The faint boundary of thered giant region corresponds approximately to the leastluminous red giants in the Hipparcos catalog (Perrymanet al. 1997), and we truncate the red giant region at anupper effective temperature of 5000 K. Stars more lumi-nous than the plotted M V ≈ . § M V val-ues collected by Li et al. (2011) for Galactic candidatesystems. Our luminosity limits are comparable to ourfaintest estimates for the luminosity of RS Oph in qui-escence, including the uncertainty in its distance in theGalaxy. The upper M V line intersects the M V – T areacorresponding to the less luminous Galactic symbioticsystem T CrB (Hachisu & Kato 2001).U Sco is a recurrent nova and supersoft X-ray sourcewith a large white dwarf mass of 1 . ± .
24 M (cid:12) (Thor-oughgood et al. 2001) and a subgiant companion. Thiscandidate progenitor system is substantially too faint fordetection in our archival images, as was the case forSN 2011fe.A candidate He-rich single-degenerate progenitor sys-tem is the He nova V445 Puppis (V445 Pup). We use theWoudt et al. (2009) estimate for M V based on a parallaxdistance measurement of 8 . ± . T (cid:46) T < (cid:12) . The plotted evolutionary tracks are models withabundance ( Z = 0 .
02) consistent with the metallicityof M82 starburst regions (F¨orster Schreiber et al. 2001).The derived luminosity limits are significantly brighterthan a hypothetical binary system of two white dwarfsthat does not experience a long-lived merger phase (Shenet al. 2012), or a white-dwarf/main-sequence binary (e.g.,Wheeler 2012).Comparison among the bright red ( R M82 V = 3 . A M82 V = 1 . R M82 V = 3 . A M82 V = 1 . R M82 V = 2 mag; A M82 V = 2 . HST broadband imaging of the site of SN 2014J are almostall greater than that of the site of SN 2011fe, and M82( d ≈ .
5; Jacobs et al. 2009) is at a smaller distancethan M101 ( d ≈ . ∼ − pix − close to the explosion site of SN 2011fe in M101, and ∼ − pix − close to SN 2014J in M82. CONCLUSIONS
We have used archival, pre-explosion
HST images ofM82 in the near-UV through near-IR to place constraintson the progenitor system of the Type Ia SN 2014J. As-suming that the extinction and selective extinction alongthe line of sight to the SN estimated from the SN lightcurve and optical spectra are approximately correct (e.g.,Goobar et al. 2014; Patat et al. 2014), we can excludea progenitor system with a bright red giant mass-donor companion, including recurrent novae with luminositiescomparable to the Galactic prototype symbiotic systemRS Oph. Our limits are fainter than the predicted lu-minosity of He-star-channel progenitors with compara-tively low effective temperature. The available near-IRM82 data provide a fainter limit for mass donors withvery low effective temperatures (
T <
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Table 1
HST
Datasets and Upper Absolute Magnitude Limits on Point-Source Flux at Explosion SiteInstrument Aperture Filter UT Date Obs. Exp. Time (s) Prop. No. Visual Limit 3 σ Background LimitWFC3 UVIS F225W 2010-01-01 1665.0 11360 26.50 26.80WFC3 UVIS F336W 2010-01-01 1620.0 11360 26.71 27.23ACS WFC F435W 2006-09-29 1800.0 10766 26.30 27.05WFC3 UVIS F487N 2009-11-17 2455.0 11360 26.01 25.94WFC3 UVIS F502N 2009-11-17 2465.0 11360 25.93 26.28WFPC2 WF F502N 1998-08-28 3600.0 6826 21.76 22.70WFC3 UVIS F547M 2010-01-01 1070.0 11360 26.14 25.94WFPC2 WF F547M 1998-08-28 100.0 6826 21.63 22.12ACS WFC F555W 2006-03-29 1360.0 10766 26.42 26.52WFPC2 WF F631N 1998-08-28 1200.0 6826 21.43 22.17ACS WFC F658N 2004-02-09 700.0 9788 24.63 24.76ACS WFC F658N 2006-03-29 4440.0 10766 25.06 25.17WFPC2 WF F658N 1997-03-16 1200.0 6826 21.31 21.86WFC3 UVIS F673N 2009-11-15 2760.0 11360 24.53 25.62ACS WFC F814W 2006-03-29 700.0 10766 24.83 25.09WFC3 IR F110W 2010-01-01 1195.39 11360 23.54 23.51WFC3 IR F128N 2009-11-17 1197.69 11360 22.90 22.85WFC3 IR F160W 2010-01-01 2395.39 11360 22.43 22.48WFC3 IR F164N 2009-11-17 2397.7 11360 21.98 22.17
Note . — Limiting magnitudes in the Vega system for point sources near the explosion coordinates in the
HST images.Visual limiting magnitudes are estimated by injecting a point source of increasing brightness in close proximity to theAO explosion coordinates, and identifying when a source is clearly detected. The 3 σ background detections are computedusing the RMS of the background measured in a region without point sources or pronounced background gradients. Table 2
Stellar and Blackbody Upper Magnitude Limits M V (2 σ ) M J (2 σ ) Most ConstrainingStar “1-Frame” Combined ‘1’-Frame Combined ‘1’-Frame BandpassO5 V -3.25 -2.53 -2.51 -1.79 F555WB0 V -3.25 -2.55 -2.55 -1.85 F555WA0 V -3.26 -2.54 -3.26 -2.54 F555WA5 V -3.26 -2.48 -3.54 -2.76 F555WF0 V -3.08 -2.37 -3.61 -2.90 F814WF5 V -2.94 -2.26 -3.76 -3.08 F814WG0 V -2.76 -2.15 -3.77 -3.16 F814WG5 V -2.69 -2.08 -3.87 -3.26 F814WK0 V -2.55 -1.95 -3.93 -3.33 F814WK5 V -2.04 -1.40 -4.21 -3.57 F814WM0 V -1.63 -0.86 -4.49 -3.72 F110WM4 V -0.09 0.57 -4.52 -3.86 F110WM5 V 0.71 1.43 -4.55 -3.83 F160WB5 III -3.25 -2.54 -2.92 -2.21 F555WG0 III -2.69 -2.03 -4.00 -3.34 F814WG5 III -2.55 -1.90 -4.09 -3.44 F814WK0 III -2.44 -1.79 -4.12 -3.47 F814WK5 III -1.81 -1.03 -4.48 -3.70 F110WM0 III -1.67 -0.86 -4.48 -3.67 F110WM5 III 0.18 0.90 -4.48 -3.76 F160WM10 III 3.84 4.42 -4.51 -3.93 F128NB5 I -3.26 -2.51 -3.09 -2.34 F555WF0 I -3.11 -2.38 -3.55 -2.82 F814WF5 I -3.04 -2.33 -3.70 -2.99 F814WG0 I -2.76 -2.13 -3.80 -3.17 F814WG5 I -2.60 -1.99 -3.91 -3.30 F814WM2 I -1.10 -0.42 -4.40 -3.72 F814WBB1 -3.25 -2.53 -2.62 -1.90 F555WBB2 -3.25 -2.53 -2.50 -1.78 F555WBB3 -3.25 -2.53 -2.45 -1.73 F555W Note . — Limiting magnitudes in V and J bands in the Vega system for a pointsource at the explosion site. The BB1, BB2, and BB3 blackbody spectra have35,000, 65,000, and 95,000 K temperatures, respectively. Stellar classifications arethose of the Pickles (1998) spectra used as models of the potential companion. Thebandpass in right column is the most constraining observation for the “1-frame”upper magnitude limits.0