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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"

16979 results found.

  1. GRB990123, optical observation
  2. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  3. GRB 990123 r-band photometry
  4. GRB 990123 Optical Follow-up
  5. GRB990123, early optical counterpart detection
  6. GRB990123, BeppoSAX WFC detection and NFI planned follow-up
  7. Optical Observations of GRB 981220
  8. GRB 981226: radio variable
  9. GRB 981226 Optical Observations
  10. GRB981226 BeppoSAX follow up
  11. GRB 981226
  12. GRB 981226 optical observations
  13. GRB 981220:Optical Observations
  14. GRB981226, BeppoSAX Christmas GRB
  15. GRB 981226 optical observations
  16. GRB 981220, radio observations
  17. GRB 981220
  18. GRB 980326/Host Galaxy
  19. BeppoSAX NFI Observation of GRB980425
  20. GRB980329 R,I flux calibration and R,I,K upper limits
  21. GRB980425 Optical Follow-up
  22. GRB970508 optical observations
  23. GRB980519, Optical Observations
  24. GRB980703 optical photometry
  25. GRB980703 optical observations
  26. GRB980703 Transient Optical Follow-Up
  27. GRB980703: LOTIS observation at early times
  28. BeppoSAX NFI observations of GRB 980703
  29. GRB 980703: ASM Position & Intensity
  30. GRB980703 optical followup
  31. Radio observations of SGRs
  32. SGR1900+14 field optical observations
  33. GRB 980613: Optical transient and its host galaxy
  34. GRB 980613: Detection of the probable host galaxy
  35. GRB 980613 Optical Observations
  36. GRB 980613 optical observations
  37. Discovery of a new SGR source, SGR1627-41
  38. GRB980613 Optical Observations
  39. GRB980613 observations from Palomar
  40. GRB980613 BeppoSAX-NFI follow up
  41. GRB980613 Near Infra-Red Observations
  42. GRB971214 Secondary Standards
  43. GRB980519 Secondary Standards
  44. GRB 980519 Optical Observations
  45. GRB 980519
  46. GRB980519 optical observations
  47. GRB 980519 Optical Observations
  48. GRB970519, optical follow-up at Schmidt Calern
  49. GRB980519 Optical Observations
  50. GRB 980519 Optical Observations
  51. GRB980515, BeppoSAX IAUC to be submitted
  52. BSAX Observations of GRB980425 field
  53. SAX J0840.7+2248 Optical Observations
  54. GRB980425: optical obs.
  55. GRB980425: Radio Observations
  56. report on BSAX observations of GRB980425
  57. GRB 980329 ROSAT observation
  58. GRB980326 X-ray Observations
  59. GRB980326, optical observations
  60. GRB980326, optical observations
  61. GRB980329 Keck K-band observations
  62. GRB980326 optical observations
  63. GRB980329 optical observations
  64. GRB980329 VLA observations
  65. GRB980329 optical observations
  66. GRB980326 optical observations
  67. Optical Observations of GRB 970508
  68. Near-IR follow-up on GRB 971227
  69. Optical Observations of the GRB 971227 field
  70. Optical Observations on GRB 971227
  71. GRB971227: Plaskett R-band observations
  72. GRB 971227: Optical clarifications
  73. GRB971227: Further CAHA R-band images
  74. GRB971227: LOTIS observations
  75. GRB971214: Optical Observations and Calibrations
  76. GRB 971214: Optical Observations
  77. Radio Observations of GRB 971214 at the VLA
  78. GRB 971024: KPNO Optical Observations
  79. GRB 970828: Palomar Observations

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