Palomar
Transient
Factory
Mark
Sullivan
(University
of
Oxford)
Law
et
al.
(2009),
PASP
121,
1395
Rau
et
al.
(2009),
PASP,
121,
1334
Palomar
48in
(1.2m)
+
CFH12k
camera
Wide‐angle,
variable
cadence
sky
survey
Looking
for
supernovae,
novae,
CVs,
planets
A
goal
of
“real‐Lme”
transient
detecLon
Why
“Factory”?
Find:
48in
Photometry:
60in
Spectra:
200in
PTF
Follow‐up
needs
to
be
global
Keck
Wise
LT
P200
WHT
Lick
Faulkes
MDM
P60
Large
programmes
on
many
faciliLes,
including
substan@al
UK
involvement
ESO
Gemini
PTF
(2009‐2013)
 
OperaLon:
 
7.8
sq
deg
field,
1”
pixels,
2”
seeing
 
60s
exposures,
15‐20s
readout
in
r,
g
(+Hα)
 
First
light
Nov
2008;
first
science
Jan
2009
 
Survey
commenced
June
2009
 
Cadences
from
1
min
to
5
days
 
In
5d
cadence,
image
pairs
one
hour
apart
idenLfy
(remove)
“rocks”
Main
Science
Goals
Exoplanet
transits
“Deepsky”
coadded
stacks
from
all
surveys
CVs
GRB
ader‐glows
Gap
transients
CVs
Type
Ia
SNe
Classical
Novae
.Ia
SNe
RR
Lyrae
Stars
Micro‐lensing
GalacLc
variable
stars
Core
collapse
SNe
Near
Earth
Objects
Eclipsing
objects
around
cool
stars
SNe
Tidal
disrupLon
flares
AGN,
QSOs,
Blazars
The
transient
universe
in
the
opLcal
Brighter
GAP?
CFH12k
single
image
2.3°
3.4°
PTF
Image
M31
as
seen
from
PTF
in
February
2009.
412
image
co‐
add.
Courtesy:
P.
Nugent
PTF
Pipeline
128
MB/90s
50
GB/night
Technical
challenges
with
the
data
•  50GB/night
of
data
must
be
processed
in
near
real‐Lme
•  Good
candidates
must
be
selected
from
thousands
of
junk
candidates
•  Fully
automated
techniques
are
very
challenging
–  Probably
the
greatest
challenge
of
any
transient
survey
PTF
Pipeline
128
MB/90s
50
GB/night
Technical
challenges
with
the
data
•  50GB/night
of
data
must
be
processed
in
near
real‐Lme
•  Good
candidates
must
be
selected
from
thousands
of
junk
candidates
•  Fully
automated
techniques
are
very
challenging
–  Probably
the
greatest
challenge
of
any
transient
survey
•  Currently
“a
lot”
of
hand‐scanning
done
“Scanning”
data
–
selecLng
candidates
Technical
challenges
with
the
data
•  50GB/night
of
data
must
be
processed
in
near
real‐Lme
•  Good
candidates
must
be
selected
from
thousands
of
junk
candidates
•  Fully
automated
techniques
are
very
challenging
–  Probably
the
greatest
challenge
of
any
transient
survey
•  Currently
“a
lot”
of
hand‐scanning
done
•  Human
interacLon
or
confirmaLon
(“scanning”)
is
sLll
an
essenLal
component
–  SNLS
had
5‐10
acLve
scanners
over
5
years
–  PTF
has
10‐15
currently
•  Scanning
is
monotonous
but
(relaLvely)
unskilful
–  “Monkeys
could
do
it”
This
is
a
panern
recogniLon
task,
which
the
human
brain
is
very
good
at
(computers
are
not)
Use
the
public
to
idenLfy
the
best
objects
Guided
by
decision
tree
Candidates
must
be
clean,
have
posiLve
pixels,
not
be
elongated
or
diffuse,
etc.
•  Fast
–
100s
of
candidates
can
be
classified
very
rapidly
(even
on
a
Saturday
night…)
•  Robust:
many
eyes
view
each
candidate
•  Training:
can
refine
automated
classifiers
•  Free
labour:
Student/postdoc
Lme
redirected
•  Object
ranking:
Candidates
ranked
combining
user
scores
•  User
ranking:
WeighLng
accounts
for
diversity
of
comments
•  Good
PR!
•  Can
probe
further
into
the
noise
and
relax
cuts
–  New
discovery
space
–  Cuts
can
be
loosened
in
real‐Lme
•  Could
be
used
for
very
rapid
(same
night)
triggering
–  Very
early
spectra/photometry
•  More
candidates
to
observe
–
rate
calculaLons
more
robust
•  Logical
extension
into
SN
host
galaxies
•  Anything
“strange
and
interesLng”
can
be
flagged
•  +
your
own
ideas
Supernova
zoo
homepage
Trial
in
October
2009
•  Used
a
WHT
run
to
trial
Galaxy
Zoo:
Supernova
•  2000
people
visited
over
2
days,
contribuLng
100,000
classificaLon
clicks
(35,000
events)
•  Public
is
very
good
at
supernova
classificaLon
•  Blogs
and
forums
keep
users
up
to
date
with
real‐Lme
observaLons
•  Site
is
not
PTF‐specific
and
will
work
with
any
survey
•  Resources
and
infrastructure
exist
and
work
PTF:
Current
status
Spectroscopic
transient
type
#
SN
Ia
193
SN
II
53
SN
Ibc
7
Unknown
SN
25
Novae
3
CV
30
Other
variable
stars
11
“Rather
weird”
3
•  PTF
is
fully
operaLonal
•  Fully
funcLoning
pipeline
and
follow‐up
scheduler
•  But…
California
“staLon”
fire
10th
biggest
fire
in
California
in
recorded
history
Dome
washing
at
Palomar
revealed
the
site
was
inundated
by
dust
and
ash
Massive
amounts
of
observing
Lme
lost
in
September,
October
and
November
last
year
Aluminium
coaLng
exposed
to
wet
wood
ash
for
2
hours
(NOTE:
This
is
the
same
substance
as
the
telescope
mirrors!)
Microscope
slide
exposed
to
dry
ash
for
14
hours
First
Science
•  TesLng
SNe
Ia
as
standard
candles
to
probe
cosmic
acceleraLon
•  Very
early
SN
(Ia)
spectra
‐
composiLon
•  Maximum‐light
HST
UV
spectra
‐
metallicity
•  Spectroscopic
telescopes
triggered
within
48‐96
hours
of
SN
explosion
•  HST
triggered
based
on
these
classificaLons,
observes
10
days
later
Timeline
Demands
very
rapid
candidate
idenLficaLon!
PTF
can
deliver
the
required
SNe
•  3
very
early
SN
Ia
sent
to
HST
in
August...
more
sent
since
then
First
PTF
science
–
a
“new”
type
of
SN
explosion
3
peculiar
SNe
Ic
found
in
PTF
All
found
in
very
low‐luminosity
host
galaxies
–
therefore
likely
low
metallicity
z=0.3‐0.5
–
much
greater
distance
than
the
bulk
of
our
SNe,
therefore
more
luminous
Spectra
No
H
or
He
Broad
UV
features
good
match
to
CII
(2200A)
and
Mg
II
(2700A),
with
some
Si
III
Reach
‐23
absolute
–
nearly
50
@mes
brighter
than
a
SN
Ia
Light
curves
Very
slow
rise
to
maximum
Fast
decay
post‐
maximum
light;
probably
not
powered
by
56Ni
decay
Reach
‐23
absolute
–
nearly
50
Lmes
brighter
than
a
SN
Ia
No
good
physical
mechanism.
Possibly
pair
instability
SNe?