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GCN Circulars

GCN Circulars are rapid astronomical bulletins submitted by and distributed to community members worldwide. They are used to share discoveries, observations, quantitative near-term predictions, requests for follow-up observations, or future observing plans related to high-energy, multi-messenger, and variable or transient astrophysical events. See the documentation for help with subscribing to or submitting Circulars.

Search for Circulars by submitter, subject, or body text (e.g. 'Fermi GRB').
To navigate to a specific circular, enter the associated Circular ID (e.g. 'gcn123', 'Circular 123', or '123').
Advanced Search

To narrow the search results, use advanced search syntax. This allows for specifying which circular field to search (submitter, subject, and/or body). For additional information, refer to the advanced search documentation.

Advanced Search Examples (click to copy):

subject:"Swift"
body:"GRB"
submitter:"Judith Racusin"

60 results found.

  1. GRB 250920B: Enhanced Swift-XRT position
  2. SVOM/sb25090605: detection of an X-ray transient from the LMXB 4U 0513-40
  3. sb25081602: Swift-XRT observations
  4. SVOM/sb25081602: detection of a likely X-ray transient
  5. The SVOM alert sb25072103 is not due to a GRB, but to a new galactic transient SVOM J195836+32283.
  6. GRB 250211A: SVOM trigger sb25021103 is not a GRB
  7. Fermi trigger No 736197684: Global MASTER-Net observations report
  8. Swift Trigger 1220736: detection of 4U 1543-62.
  9. Trigger 1160641: Swift detection of 4U 1630-472 (a.k.a. SWIFT J1633.8-4724A)
  10. Trigger 1062273: Swift detection of 4U 1700-377
  11. Swift-BAT Trigger 1055000/GRB210612.54: MASTER optical source observation
  12. Swift-BAT Trigger 1055000: Swift detection of an outburst from 4U 1543-47
  13. Swift trigger 1047857 is 4U 1700-377
  14. GRB 210421A: Swift/UVOT Upper Limits
  15. GECAM detection of a burst possibly from the X-ray burster 4U 0614+09 or GRB 210124A
  16. GRB 201103B: AGILE detection
  17. GRB 201029A: Swift-XRT refined Analysis
  18. LIGO/Virgo S191222n: Updated Sky Localization
  19. LIGO/Virgo S190718y Global MASTER-Net observations report
  20. Fermi trigger No 583567803 Global MASTER-Net observations report
  21. Trigger 888312: Swift detection of 4U 1901+03
  22. Swift trigger 831888: misidentification of 4U 1416-62
  23. Fermi GBM Detection of possible burst from AXP 4U 0142+61
  24. GRB 170113A: Swift/UVOT Observations
  25. Swift Trigger 718766 is not an astrophysical event.
  26. Swift Trigger 707545 is likely 4U 1850-03/GS1843-02
  27. GRB 160409A found in Swift BAT ground analysis
  28. Swift detection of 4U 1850-03
  29. GRB 150301A: Fermi GBM observation
  30. Swift-BAT refined analysis of magnetar 4U 0142+61 (Trigger 632888)
  31. Fermi GBM Observations of Magnetar 4U 0142+61
  32. Trigger 632888: Swift detection of the magnetar 4U 0142+61
  33. Trigger 631747: Swift detection of 4U 0614+09
  34. Swift detection of 4U 1700+24 (= V* V934 Her)
  35. Swift detection of 4U 1700+24 (= V934 Her)
  36. Swift detection of outburst from 4U 1700+24
  37. Swift trigger 609139 is probably 4U 1850-03
  38. GRB 130816A: Swift/UVOT Upper Limits
  39. Swift Trigger 558828 is not an interesting event
  40. Swift Trigger 557674 was due to an onboard position error
  41. Swift Trigger 530581: GRB 120811A or a galactic transient
  42. Swift detection of 4U 1630-47
  43. GRB 120311A: Swift/UVOT Upper Limits
  44. AXP 4U 1042+61: Mondy optical observations
  45. AXP 4U 0142+61: Swift-BAT refined analysis (trigger 511611)
  46. Swift detection of an SGR burst from AXP 4U 0142+61
  47. SGR J1834.9-0846: A Neutron Star in W41?
  48. AXP 4U 0142+61: Fermi GBM detection
  49. AXP 4U 0142+61: Swift-BAT refined analysis
  50. Swift detection of a SGR-like burst from the AXP 4U 0142+61
  51. Swift trigger on 4U 1700-377 while star tracker loss-of-lock
  52. GRB 070628 Swift-UVOT Refined Analysis
  53. Retractions of previous Swift-BAT triggers
  54. Swift detection of an outburst from the 4U 1246-58 LMXB burster
  55. GRB060602A: Swift/UVOT upper limits
  56. IBAS GRB Alerts 1978-1980
  57. GRB040903 - A XRF?
  58. GRB030131: Candidate Optical Afterglow
  59. IPN detection of possible bursts from SGR1806-20
  60. GRB980326 X-ray Observations

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