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VLASS SSG Meeting Notes
Observing and data processing status – Amy Kimball, Mark Lacy
Epoch 3.1 is 72% observed
BnA at the end of May for the rest
QL imaging is 43% complete, automated QA going well
No more SE imaging yet
Updates from working groups:
Extragalactic - Kate Alexander, Heinz Andernach
New paper on arXiv:2303.12830 by Gordon+23 (DRAGN hunting)
Galactic - Laurant Loinard, Adam Ginsburg
Galactic pulsars (Shami + Dillon discussed at DSA-2000 meeting)
Transients - Gregg Hallinan, Greg Sivakoff
Deadline for abstracts in 2 weeks!
New transient identified by Yuyang Chen (point source inside galactic supernova remnant)
Dillon’s transient catalog is progressing, real time transient identification of transients coming soon to go after faster transient pops - open to ideas
Polarization - Bryan Gaensler, Jennifer West
New cubes being analyzed (pol + spectral indices from cubes; spix being compared with other CIRADA products)
POSSUM collaboration
New computing resources
Commensal - Wendy Peters, Chenoa Trembley
Data Products - Dillon Dong, Erik Rosolowsky
Science communication - Brian Kent, Erik Murphy
NRAO will send announcement today about activities at AAS, VLASS splinter
EPO - Jacob Noel-Storr, Summer Ash
VLA open house on April 1, public talks
Other topics?
CIRADA Epoch 2 VLASS catalog status?
Sidelobe detection between QL and SE under investigation . . .
Sidelobe probability/other flags for this catalog currently being explored
Science presentation - VLASS Epoch 4 (Mark Lacy)View file name Epoch4_for_SSG.pdf height 250 - 1900 hr of time (in addition to 5600 hr for first 3 epochs)
- 4.1 would start in 2025, 4.2 in 2026/2027
- Science
- VLASS has demonstrated important new science on slow transients (especially via comparison to FIRST)
- Epoch 4 would allow us to reduce the gap between VLASS Epoch 1-2 and FIRST
- VLASS remains unique compared to other transient surveys in terms of resolution and frequency coverage
- Variations in polarimetry remains unexplored
- Slightly better SNR for faint sources in coadds (probe well into SF galaxy population with improved sensitivity)
- Logistics
- Improve commensal survey datasets (VCSS and COSMIC had some issues in 3.1)
- VLASS1.1 was compromised due to antenna pointing issues
- Key opportunity: VLASS could be a good transitional project from VLA to ngVLA, also complementary to DSA-2000 timescale (stepping stone
)- SSG input:
- Tasks:
- SSG would need to write the science case for a 4th epoch of VLASS
- Science pitch due at the end of the month (Mark Lacy will lead this)
- If full proposal requested by NRAO, SSG will write the bulk of it
- Additional science ideas?
- Fast processing use case ideas (Galactic transients, Dillon) - R&D potential for pioneering new techniques
- Strategy?
- Continue with current cadence and observing strategy
- Could skip a configuration or two
- Might be beneficial for some transient science cases (Dillon)
- Could do a C-config epoch to fill in short baselines
- Would be valuable for low-surface brightness sources (Heinz)
- But this would lead to challenges for transient identification/host matching (Dillon)
- Complications for variable AGN science (Kate)
- Could do a C-band survey instead (comes with new challenges)
- Imaging heuristics easier
- Data volume larger
- Harder to compare with transient data
- Spix info (e.g. peaked spectrum/young sources, including AGN and TDEs), broader band pol
- For transient science cases, better to stick to same frequency (Kate)
- Cost of producing and storing >3 sets of SE? 1+2+3+4 co-adds would be challenging computationally/resource wise
- Would need BnA in the schedule
- Challenges
- Mitigation measures for workload of staff/DA
- NOTES:
- LSST synergy with 2025 start to 4.1 (Dillon)
- CASA has a GPU gridder under development, faster (SE) imaging (Juergen)
- Would open up opportunities for catching faster transients
- Current delay between processing and QL images is 30 days
- Now that we have everything in place, we would need relatively little development of infrastructure (Juergen)
- Question: could we do OTF testing in C-config to get guidance on how it would work (Tracy)?
- Yes, Steve has tested this for COSMOS field at C-band/C-config
- Needs a strong science case to be worth it (Shami, Bryan)
- Single epoch data processing
- Community proposal opportunity?
- Level of SSG interest?
- Mark, Dillon, Jennifer, Kate - informal Google form?
- Timescale?
- Logistics?
- Suggestions: Deep fields (Stripe 82, CDFS, etc. . .
- )
- Mark, Steve- Galactic Plane - Dillon
- Science targets of interest (transients, AGN . . . )
- Outreach - identify and prioritize VLASS images to feature in the NRAO Science and Facilities brochure (currently features quicklook images) - Brian Kent
- Community solicitation (“SE data processing proposal”) - Kristina
- Polarization products - Mark Lacy
- Events:
- Conferences of interest?
- New Eyes on the Universe: SKA and ngVLA (May 1-5, 2023)
- Registration deadline is April 7
- Any interest in having a VLASS break-out session? - Chenoa
- Splinter session update for AAS #242 (June 2023) – Steve Myers
- Reminder: abstracts for talks at the AAS242 meeting (not in the splinter session, that is separate) are due 11 April if you want to give one in another session.
- Early registration for the meeting ends Apr 20 (you have to be registered for the meeting to attend the Splinter in person, though not for the Splinter online Zoom).
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Reference material:
- Terms of reference document: pdf
- VLASS Slack workspace and SSG channel (contact Bryan Gaensler)
- Confluence page
- Next meeting: Monday, April 2nd at 1pm EST / 11am MST / 18:00 UTC