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diff --git a/Discussion.tex b/Discussion.tex
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\section{Discussion}
\label{sec:Discussion} \section{Discussion}\label{sec:Discussion}
We have found that the \spock transient events are phenomenologically
most consistent with RNe and LBVs. Let us now consider
the astrophysical implications of these two possible classifications.
We have found that three models offer plausible explanations for the
\spock events: these transients are due to a RN
Our preferred explanation for the \spock events is
that we have observed two distinct eruptive episodes from a massive
LBV star. The light curve shape is consistent with rapid LBV
eruptions seen in systems such as SN 2009ip and NGC 3432-LBV1. The
peak luminosity and recurrence timescale are also within the bounds of
what has been observed from nearby LBVs. The \spock episodes may have
been among the fastest and most luminous of any rapid LBV events yet
observed. However, no other rapid LBV outbursts have yet been observed
with such a high cadence, so the detailed light curve shape can not be
rigorously compared against other events. In this scenario, the
\spock LBV system would most likely have exhibited multiple eruptions
over the last few years, but most of them were missed, as they landed
within the large gaps of the \HST Frontier Fields imaging program.
We speculate that the very luminous and very fast \spock transients
may be driven by extreme mass eruption events or an extreme form of
stellar pulsation. Both of these mechanisms are likely to occur in
LBV progenitor stars, but we do not have a robust model for precisely
how LBV eruptions are generated. This is a topic in need of
significant theoretical work, with the end goal being a comprehensive
physical model that accommodates both the \etacar-like great eruptions
and the S Dor-type variation of LBVs. The \spock events are extreme
in several dimensions, and will only add to this theoretical
challenge.
diff --git a/Introduction.tex b/Introduction.tex
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...
\section{Introduction}\label{sec:Introduction}
The
Spock transient
events events---separately designated \spockone and
\spocktwo (collectively
nicknamed ``Spock'') appeared \spocktwo---appeared in Hubble Space Telescope (\HST) imaging collected
in January and August of 2014,
respectively. respectively (Figure
\ref{fig:SpockDetectionImages}). These images were centered on the galaxy
cluster \MACS0416\ (hereafter, MACS0416) and were collected as part of
the Hubble Frontier Fields (HFF) survey (HST-PID:13496, PI:Lotz), a
multi-cycle program
observing for deep imaging of 6 massive galaxy clusters and
associated ``blank sky''
parallel fields
with very
deep imaging. observed in parallel.
The Combining the \HST imaging and
modeling lens models of the
MACS0416 gravitational
lens
lead leads to three key observables for the \spock events: (1) they are
both more luminous than a classical nova, but less luminous than
almost all supernovae (SNe), reaching a peak luminosity of roughly
$10^{41}$ erg s$^{−1}$ ($M_V=−14$); (2) both transients exhibited fast
light curves, with rise and decline timescales of $\sim2--5$ days in
the rest frame;
and (3) it is likely that both events arose from the
same physical location but were not coincident in time---they were
probably separated by 3-5 months in the rest frame.
These peculiar
transients thus present an intriguing puzzle: they are broadly
consistent with the expected behavior of stellar explosions (they each
exhibit a single isolated rise and decline in brightness), but they
can not be trivially classified into any of the common categories of
explosive or eruptive astrophysical transients.
% Until recently, most surveys searching for extragalactic optical
% transients have been optimized for the discovery of SNe, and
% particularly for Type Ia SNe, because of their value as cosmological
% probes \citep[e.g.,][and references therein]{Weinberg:2013}. These
% surveys have favored a cadence of several days between return visits,
% with relatively short exposures to maximize the area of sky covered
% while remaining sensitive to their primary targets---relatively bright
% Type Ia SNe. Although recent surveys are beginning to discover more
% and more categories of rapidly changing optical transients
% \citep[e.g.][]{Kasliwal:2011,Drout:2014} most programs remain largely
% insensitive to transients with peak brightness and timescales
% comparable to the \spock events \citep{Berger:2013}. Future
% wide-field observatories such as the Large Synoptic Survey Telescope
% \citep[LSST,][]{Tyson:2002} will be much more efficient at discovering
% such transients, and can be expected to reveal many new categories of
% astrophysical transients.
The HFF survey was not designed with discovery of peculiar
extragalactic transients as a core objective, but it has
unintentionally opened an
early unusual window of discovery for such events.
Very faint sources at relatively high redshift in these fields are
made detectable by the substantial gravitational lensing magnification
of the foreground galaxy clusters. Very rapidly evolving sources are
...
into multiple resolved images \citep{Kelly:2015a}. The HFF imaging
program has also enabled a precise measurement of the lensing
magnification for SN Tomas, a high-redshift Type Ia SN
\citep{Rodney:2015a}. Both of those SNe constitute fairly
normal common
astrophysical phenomena, and the possibility of discovering such
transients was anticipated at the start of the HFF program. \spock,
however, appears to be {\it sui generis}. No single astrophysical
diff --git a/LensingModels.tex b/LensingModels.tex
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\section{Constraints from \section{Gravitational Lens
Model}\label{sec:LensingModels} Models}\label{sec:LensingModels}
To interpret the observed light curves and the timing of these two
events, we use \textcolor{red}{five} cluster mass The five lens models
used to provide estimates of the
magnification plausible range
of magnifications and time delays
from gravitational
lensing. We identify each by the last name of the principal
investigator of the development team: are:
\textcolor{red}{NOTE: THESE
DESCRIPTIONS ARE PROBABLY INCORRECT. MODELERS, PLEASE FIX AS
NEEDED.}
\bigskip
...
light-traces-mass assumption and parameterizes cluster components
using Navarro-Frenk-White (NFW) density profiles
\citep{Navarro:1997}.
\item{\it
Oguri:} Kawamata:} The model of \citet{Kawamata:2015}, built using the
{\tt GLAFIC}
software\footnote{\url{http://www.slac.stanford.edu/~oguri/glafic/}}
with strong-lensing constraints.
...
methodology of each model and a comparison of the magnification
predictions and uncertainties across the entire \macs0416 field.
These models provide estimates for the absolute magnifications due to
gravitational lensing from the \macs0416\ cluster, reported in
Table~\ref{tab:LensModelPredictions}. Collectively, the models
predict magnification values between about $\mu=10$ and $\mu=100$ for
both events. This wide range is due primarily to the close proximity
of the \spock\ events to the lensing critical curve for sources at
$z=1$. Note that the magnifications for \spockone\ and \spocktwo\ are
highly correlated. A variation of a given lens model that moves the
critical curve closer to the position of \spockone\ would drive the
magnification of that event much higher (toward $\mu_1\sim100$), but
that would also have the effect of moving the critical curve farther
from \spocktwo\, which would necessarily drive its magnification
downward (toward $\mu_2\sim10$). \todo{add a citation for the general
trait of model uncertainty increasing near critical curves}
%\renewcommand{\arraystretch}{1.5}
\begin{deluxetable}{lccccc}\label{tab:LensModelPredictions}
\tablewidth{\linewidth} \tablecolumns{6} \tablecaption{Lens model
predictions for time delays and
magnifications\label{tab:LensModelPredictions}} \tablehead{
\colhead{Model} & \colhead{$\Delta t_{\rm NW:SE}$} & \colhead{$\Delta
t_{\rm NW:11.3}$} & \colhead{$\mu_1$} & \colhead{$\mu_2$} &
\colhead{$\mu_3$}\\ \colhead{} & \colhead{(days)} &
\colhead{(years)} & \colhead{} & \colhead{} & \colhead{} }
\startdata
Diego & -48$\pm$10 & 0.8 & 35$\pm$20 & 30$\pm$20 &\\[0.5em]
Jauzac & -16 $\pm13$ & -2.4 $^{+0.5}_{-0.6}$ & 37 $\pm3$ & 18 $\pm2$ & 4.6 $\pm0.1$\\[0.5em]
Oguri & 4.1 $^{+5.5}_{-3.4}$ & -5.0 $^{+0.5}_{-0.6}$ & 29 $^{+43}_{-10}$ & 84 $^{+103}_{-38}$ & 3.0 $^{+0.2}_{-0.2}$\\[0.5em]
Williams & -10 $^{+1}_{-7}$ & -2.5 $^{+1.0}_{-3.1}$ & 13 $^{+11}_{-6}$ & 12 $^{+9}_{-5}$ & 3.1 $^{+2.2}_{-0.9}$\\[0.5em]
Zitrin & 42 $^{+13}_{-9}$ & -3.7 $\pm0.3$ & 90 $^{+61}_{-27}$ & 32 $^{+8}_{-10}$ & 3.6 $^{+0.2}_{-0.5}$\\
\enddata
\tablecomments{Time delays give the predicted delay relative to an
appearance in the NW host image, 11.2. Positive (negative) values indicate the
NW image is the leading (trailing) image of the pair.
\todo{Need to update with latest Jauzac models!}
}
\end{deluxetable}
%\renewcommand{\arraystretch}{1.}
From each model we also extract two time delay predictions, given in
Table~\ref{tab:LensModelPredictions}. We report all time delays
relative to the \spockone\ event, which appeared in January 2014 in
host image 11.2. That same transient episode would have appeared at
different times in host galaxy images 11.1 and 11.3, due primarily to
the \citet{Shapiro:1964} delay. The $\Delta t_{\rm NW:SE}$ column in
Table~\ref{tab:LensModelPredictions} gives the model predictions for
the number of days between the appearance of the \spockone\ event in
the NW host image (11.2) and the date when it should have been
observable in the adjacent SE host image (11.1). The opposite value
would give the time difference between the August 2014
\spocktwo\ event and its expected appearance in host image 11.2.
Table~\ref{tab:LensModelPredictions} also reports the predicted time
delay (in years) between appearance in the NW host image 11.2 and the
more widely separated image 11.3.
Figure~\ref{fig:LensModelContours} presents probability distributions
derived from these models for the three magnifications and two time
diff --git a/LightCurves.tex b/LightCurves.tex
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\section{Light Curves}\label{sec:LightCurves}
The two \spock\ events exhibited very similar light curves, as shown
in Figures \ref{fig:LightCurves}. The January event, \spockone, rises
to peak luminosity and fades back to quiescence in only $\sim$7 days,
and the August event, \spocktwo, rises and falls in $<20$ days.
Due to the rapid decline timescale, no observations were collected for
diff --git a/Observations.tex b/Observations.tex
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...
MUSE is an integral field spectrograph, these observations also
provided a confirmation of the redshift of the third image of the host
galaxy, 11.3, with a matching \ionline{O}{[ii]} line at the same
wavelength.
The MUSE data also provide useful spatial resolution of
the \ionline{O}{[ii]} signal, allowing examination of possible
substructure in the host images 11.1 and 11.2 (see
Section~\ref{sec:HostGalaxy}. \todo{Make a figure showing the [OII] at
z=1.0054 slice from the MUSE IFU data cube} \input{muse_linefits}
The MUSE data also provide spatial resolution of the
\ionline{O}{[ii]} signal, allowing examination of possible
substructure in the host images 11.1 and 11.2 (see
Section~\ref{sec:HostGalaxy}. As reported in
Table~\ref{tab:muselinefits} \ionline{O}{[ii]} lines do not exhibit
any discernible gradient across the host galaxy images in terms of the
wavelength of line centers, full width at half maximum, or the
intensity ratio of the two components of the doublet. Thus, the
\ionline{O}{[ii]} measurements from MUSE can not be used to
distinguish either \spock location from the other, or to definitively
answer whether either position is coincident with the center of the
host galaxy. We conclude that it is plausible but not certain that
the two \spock events arose from the same physical location in the
host galaxy.
A final
potential source
for redshift of spectroscopic information relevant to \spock
is the Grism Lens Amplified Survey from Space \citep[GLASS; PID:
HST-GO-13459; PI:T. Treu][]{Schmidt:2014,Treu:2015a}. The GLASS
program collected slitless spectroscopy on the \macs0416 field using
...
redshift catalog\footnote{\url{http://glass.astro.ucla.edu/}} that
have a spectroscopic redshift consistent with z=1.0054.
Table \TODO{(add a table with photometry)} %~\ref{tab:Photometry}
and Figure~\ref{fig:LightCurves} present
photometry of the \spock\ events
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\label{fig:SpockDetectionImages}
The detection of \spockone and \spocktwo in HST imaging from the
Hubble Frontier Fields. The central panel shows the full field of the
MACSJ0416 cluster, in a combined image using optical and infrared
bands from HST. Two boxes
in within the main panel
highlight demarcate the regions
where the \spock host galaxy images appear.
The These regions are shown as
two inset panels on the left, highlighting the three
images of the
host galaxy
images (labeled 11.1, 11.2, and
11.3) 11.3), whcih are
shown in two inset panels on caused by the
left. gravitational lensing of the cluster. Two columns on the right side
show the discovery of the two
transient events in optical and infrared
light, respectively. In these final two columns the top row is a
template image, the center row shows the epoch when each transient
appeared, and the bottom row is the difference image.
diff --git a/figures/peakluminosity_vs_declinetime/peakluminosity_vs_declinetime.pdf b/figures/peakluminosity_vs_declinetime/peakluminosity_vs_declinetime.pdf
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Abstract.tex
Introduction.tex
figures/detection_image/detection_image.png
Observations.tex
figures/spock_lightcurves/spock_lightcurves_flux.png
figures/light_curve_linear_fits/light_curve_linear_fits.png Results.tex
figures/peakluminosity_vs_declinetime/peakluminosity_vs_declinetime.png
Discussion.tex
Acknowledgments.tex
Methods.tex
Observations.tex
LightCurves.tex
figures/light_curve_linear_fits/light_curve_linear_fits.png
figures/spock_colorcurves_observerframe/spock_colorcurves_observerframe.png
HostGalaxy.tex
figures/spock_hostgalaxy_properties/spock_hostgalaxy_properties.png
figures/muse_oii_sequence/muse_oii_sequence.png
LensingModels.tex
figures/composite_lens_model_contours/composite_lens_model_contours.png
figures/peakluminosity_vs_declinetime_wide/peakluminosity_vs_declinetime_wide.png
figures/peakluminosity_vs_declinetime/peakluminosity_vs_declinetime.png
figures/spock_predictions/spock_predictions.png
Classification.tex
figures/composite_lens_model_contours/composite_lens_model_contours.png
figures/recurrent_nova_lightcurve_comparison/recurrent_nova_lightcurve_comparison.png
figures/lbv_lightcurve_comparison/lbv_lightcurve_comparison.png
Classification.tex
figures/recurrent_nova_recurrence_comparison/recurrent_nova_recurrence_comparison.png
Conclusions.tex
Acknowledgments.tex
diff --git a/muse_linefits.tex b/muse_linefits.tex
new file mode 100644
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...
\begin{deluxetable*}{rllc ccc ccc c}
\tablewidth{\linewidth}
\tablecolumns{12}
\tablecaption{Measurements of the \ionline{O}{[ii]} $\lambda\lambda$3626,3629 lines from \spock host galaxy images 11.1 and 11.2\tablenotemark{a}}
\tablehead{ \colhead{Aperture} & \colhead{R.A.} & \colhead{Dec.} & \colhead{distance to} & \multicolumn{3}{c}{\ionline{O}{[ii]} $\lambda$3726} & \multicolumn{3}{c}{\ionline{O}{[ii]} $\lambda$3729} & \colhead{Line}\\
\colhead{ID} & \colhead{J2000} & \colhead{J2000} & \colhead{\spocktwo} & \colhead{Flux} & \colhead{$\lambda_{\rm center}$} & \colhead{FWHM} &
\colhead{Flux} & \colhead{$\lambda_{\rm center}$} & \colhead{FWHM} & \colhead{Ratio}\\
& \colhead{(degrees)} & \colhead{(degrees)} & \colhead{(Arcsec)} & \colhead{(erg\,s$^{-1}$\,cm$^{-2}$)} & \colhead{(\AA)} & \colhead{(\AA)} &
\colhead{(erg\,s$^{-1}$\,cm$^{-2}$)} & \colhead{(\AA)} & \colhead{(\AA)}}
\startdata
1 & 64.039371 & -24.070450 & -1.54 & 2.19e-18 & 7472.37 & 4.00 & 3.57e-18 & 7478.17 & 4.00 & 1.63\\
2 & 64.039218 & -24.070345 & -0.88 & 4.73e-18 & 7472.16 & 4.00 & 5.30e-18 & 7478.12 & 3.40 & 1.12\\
3 & 64.039078 & -24.070264 & -0.30 & 5.05e-18 & 7472.29 & 4.00 & 6.10e-18 & 7478.27 & 3.73 & 1.21\\
4 & 64.038921 & -24.070163 & 0.39 & 4.22e-18 & 7472.19 & 4.00 & 5.74e-18 & 7478.08 & 3.59 & 1.36\\
5 & 64.038785 & -24.070078 & 0.97 & 3.86e-18 & 7472.25 & 4.00 & 6.56e-18 & 7478.19 & 4.00 & 1.70\\
6 & 64.038637 & -24.069958 & 1.65 & 4.80e-18 & 7472.51 & 4.00 & 5.42e-18 & 7478.07 & 2.69 & 1.13\\
7 & 64.038501 & -24.069865 & 2.24 & 4.60e-18 & 7472.57 & 3.43 & 5.74e-18 & 7478.17 & 3.20 & 1.25\\
8 & 64.038352 & -24.069752 & 2.92 & 4.70e-18 & 7472.54 & 3.54 & 6.22e-18 & 7478.16 & 2.95 & 1.32\\
9 & 64.038229 & -24.069648 & 3.50 & 3.26e-18 & 7472.83 & 2.80 & 5.79e-18 & 7478.16 & 2.84 & 1.77\\
10 & 64.038076 & -24.069532 & 4.19 & 2.44e-18 & 7473.01 & 2.57 & 3.22e-18 & 7478.10 & 2.73 & 1.32\\
Spo-1 & 64.038565 & -24.069939 & 1.90 & 4.30e-18 & 7472.55 & 3.13 & 5.49e-18 & 7478.01 & 2.89 & 1.28\\
Spo-2 & 64.038998 & -24.070241 & 0.00 & 4.37e-18 & 7472.46 & 4.00 & 6.10e-18 & 7478.22 & 3.79 & 1.40\\
\enddata
\tablenote{Properties of the of the \ionline{O}{[ii]} lines were
derived from 1-D spectra extracted from the MUSE data cube at 10
locations spaced 0\farcs6 apart along the length of the arc that
comprises images 11.1 and 11.2 of the \spock host galaxy. Each
extraction used an aperture of 0\farcs6 radius, centered on the
mid-line of the host galaxy arc. The integrated line flux, observed
wavelength of line center ($\lambda_{\rm center}$), and full width
at half maximum (FWHM) were found by fitting a Gaussian profile to
each component of the doublet.}
\label{tab:MuseLineFits}
\end{deluxetable*}
%# ID RA DEC Delta_spock2 OII]3726 OII]3729 OII]3729/OII]3726
%# Arcsec Flux(erg/s/cm^2) Center(Angstrom) Amplitude(erg/s/cm^2) FWHM(Angstrom) Flux(erg/s/cm^2) Center(Angstrom) Amplitude(erg/s/cm^2) FWHM(Angstrom)
%# ID RA DEC d_spock2 flux3726 wave3726 amplitude3726 fwhm3726 flux3729 wave37269 amplitude3729 fwhm3729 fluxratio3729to3726
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diff --git a/title.tex b/title.tex
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...
A Two Peculiar Fast
Transient Transients in a Strongly Lensed Host Galaxy
