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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"

24279 results found.

  1. GRB990123, Upcoming HST Service Observations
  2. GRB990123 Optical Observations
  3. GRB990123, Probability of gravitational lensing
  4. GRB 990123: Continued Radio Observations
  5. GRB990123, Preliminary Lens Search Results
  6. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  7. On the Lensing Interpretation of GRB 990123
  8. Search for Potential Images of GRB 990123
  9. GRB990123, Optical BVRI Observations
  10. GRB 990123: near-infrared observations.
  11. GRB990123, OSSE observations
  12. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  13. GRB 990123 Spectroscopic Redshifts
  14. GRB 990123 optical observations
  15. GRB990123 optical observations
  16. GRB990123, Optical observation
  17. GRB 990123: Optical Decay Slope
  18. GRB990123, early optical counterpart detection
  19. GRB990123 Optical Observation
  20. GRB 990123: Bright New Source, Possible Optical Transient
  21. Possible identification of SN1999E with GRB980910
  22. Optical Observations of GRB 981220
  23. GRB981220
  24. GRB981220, Correction to GCN 179
  25. GRB 981220 Optical observations
  26. GRB 981226
  27. GRB 981220
  28. GRB 981220, radio observations
  29. GRB981226 Optical Observation
  30. GRB 981220: BeppoSAX/GRBM results
  31. GRB981220 I-band Observations
  32. GRB981220 Optical Observations
  33. GRB 981220
  34. GRB 980326/Host Galaxy
  35. GRB 981220: RXTE/ASM and BeppoSAX/GRBM results
  36. GRB 980923 BATSE Observations
  37. GRB970508 optical observations
  38. Optical Observations of the Host Galaxy of GRB 980519
  39. GRB980519, Optical Observations
  40. GRB980703 H-band Observations
  41. GRB980703: LOTIS observation at early times
  42. GRB 980703: ASM Position & Intensity
  43. GRB980519 observation report
  44. GRB980703 optical followup
  45. GRB980613, optical observations
  46. GRB 980613: BATSE Observations
  47. Discovery of a new SGR source, SGR1627-41
  48. GRB 980519 Optical Observations
  49. GRB 980519 Optical Observations
  50. GRB970519, optical follow-up at Schmidt Calern
  51. GRB980519 optical observations
  52. GRB980519 Optical Observations
  53. GRB980515, BeppoSAX IAUC to be submitted
  54. GRB980519, BeppoSAX-WFC updated position
  55. GRB 980425 Radio Light Curve
  56. GRB 980425 Brightness Temperature
  57. GRB 980329 ROSAT observation
  58. GRB980326, optical observations
  59. GRB980326, optical observations
  60. GRByymmdd, Announcement of automation
  61. GRB980329 sub-millimeter observations
  62. GRB980329 optical observations
  63. GRB980329 optical observations
  64. GRB980326 optical observations
  65. GRB980326 optical observations
  66. Optical Observations of GRB 970508
  67. GRB 971214: Redshift from Keck Observations
  68. Near-IR follow-up on GRB 971227
  69. Optical Observations of the GRB 971227 field
  70. Optical Observations on GRB 971227
  71. GRB 971214: Redshift from Keck Optical Observations
  72. GRB 971214: Redshift from Keck Optical Observations
  73. Optical Observations of GRB 971214 at Keck
  74. GRB 971214: USNOFS Observations Summary
  75. GRB 971024: Refined analysis by USNOFS Observations
  76. GRB 971024: USNO Observations
  77. GRB 970925: BATSE Localization
  78. IRAS 18119-1342 and the possible new SGR
  79. GRB 970828: Palomar Observations

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