HeViCS/HeFoCS SPIRE Data Status and future releases Extended HRS Profiles Current Results Matthew Smith [email protected] c.uk
Jan 02, 2016
HeViCS/HeFoCSSPIRE DataStatus and future releases
Extended HRS ProfilesCurrent Results
Matthew Smith
Last Version: DR3.5
Released June 2012
Pipeline: Optimised De-glitcher BriGAdE Allow Dark Pixel drift
removal Manual Jump and
glitch-tail removal New Pixel sizes:
6, 8, 12"
HeFoCS
HeViCSV1
V2
V3
V4
Latest Version: DR4
Released June 2012
Updates from DR3.5 to DR4: PMW cal factor v5 to v8
applied to map (1.0067) Second-order deglitching Relative Gain Corrections
for extended emission
For extra-galactic science we have optimum SPIRE pipeline (cirrus scale structures may-not be optimal)
Pointing Products Star-Tracker Temperatures were changed on
OD 320 to prevent hot-pixel issues Herschel updated on OD 761 to account for
changes New pointing products OD 320-761 available
(~ 2")
Herschel Map-Making Workshop?
Data Release 5
Planned Updates on DR4 NEW CALIBRATION!
(point + ext) New Pointing Product
Updates not going to be applied Planck Zero Level Calibration De-striper (except on a set of cirrus maps for
Simone
New Neptune measurements by George Increase of ∼3% , ∼2% & ∼1% at 250, 350 and
500µm
Aperture Efficiency values now included (fairly small)
Long term – will be new updates on the assumed Neptune and Uranus models
Point Source Calibration
Chris North, Matt Griffin, & co
Applies to fully extended until >100'
Working on adaptive script for intermediate sources 10 – 100'.
Extended Calibration
Will require TWO versions of SPIRE for point/extended or even individual object maps that are
optimised to their size
Old Philosophy – FUDGE IT: Modify the filter curve with a λ2 weighting
Wrong for 2 reasons: 1: Beam solid angle varies as λ1.7 2: Not a single value of beam area appropriate for sources
Depending on your source spectral index could correct the wrong way.
Extended Calibration (2)
Why the difference? See white board!
New Philosophy As well as apply colour–corrections account for varying
beam area across band Talking somewhere in the region 0-10% change in values
New pipeline surface brightness product in MJy/sr
Is a Planck zero level corrected map as well (but not really worth it)
Extended Calibration (3)
An original aim of the HRS (and many other surveys) to find cold dust in outskirts of galaxies.
Dust could be driven out or formed outside disk.
Has been detected by quasar absorption (Menard et al. 2010) – see next slide.
Not been possible to detect emission before as dust is cold and very low surface brightness.
Still work in progress...
Extended Dust (bonus chapter!)
Potential Questions? How far can we detect dust emission What are the properties of the dust at these
wavelengths Extreme environment for SF etc…
Only used SPIRE only due to sensitivity / reduction method / areas covered
Still work in progress
Extended Dust (2)
uses SDSS
∼85,000 quasars at z > 1
Correlated with 24 million galaxies at z∼0.3
Find reddening and magnification
Half of dust is outside galaxies
Menard et al. 2010
Stacked Radial ProfilesHRS object Criteria:
• Late-type galaxies
• Indentified as detection
• Extended Source
• No other bright contaminating object
• No heavy cirrus contamination
• Inclination < 60°
Have randomly chosen 32 galaxies (1/4 sample) and repeated procedure
Measured where it crosses a fixed threshold (equivalent to 1.8R25)
Repeated 40,000 times
Results do not vary by a large amount (±0.15 R25)
Monte-Carlo Tests
Probably Not!
Can other Surveys do better?
Nearby Objects
Large extended objects
Bright
Maps not large enough
Wide Field Surveys, e.g., H-ATLAS
Many objects so can be sensitive
Large areas so can reach high scales
Angular size is smaller, flux of central beam dominates at radii < 2.0R25
Minimise χ2 model by: Trial Model Convolving it with beam Calculate χ2
Following Schruba et al. 2011 do not fit centre 30˝ Need 2 exponentials
Best-Fit Model
The fraction of dust emission between 1-2 R25 is 6.6, 8.0 and 10.6% for the 250, 350 and 500µm band.
If integrate the broken-exponential model from 0⇢∞ find that 4.2% of emission at 250µm
Rough agreement with 15kpc Medard value but I need to redo this.
Stacked Radial Profiles (2)
Temperature Results Work in Progress… All images smoothed and re-gridded to
PLW images Temperature stabilises around 16K Means a higher fraction of dust mass
outside R25 than fraction 250µm emission
HIDeficienc
y Difference is less
prounonced as Cortese 2010
Individual objects are in agreement
Highly HIdef are significantly different from HIdef < 0.0 (Mann-Whitney U statistic)
Stellar
Mass
Are low mass galaxies cosmic hoovers picking up dust expelled from high stellar mass galaxies?
Schruba et al. with CO with HERACLES reach 1.0-1.2R25
Other Tracers
HI Paolo Serra suggested a thesis by Thomas Martinsson
Unknown for other wavelengths (e.g., UV)?