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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"

24937 results found.

  1. GRB990123, 15-GHz limits
  2. GRB 990123: New Constraints on Possible Foreground Galaxies
  3. GRB990123 Optical Observations
  4. GRB990123, Probability of gravitational lensing
  5. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  6. GRB990123, Preliminary Lens Search Results
  7. On the Lensing Interpretation of GRB 990123
  8. Search for Potential Images of GRB 990123
  9. Search for Potential Images of GRB 990123
  10. GRB990123, Optical BVRI Observations
  11. GRB 990123: near-infrared observations.
  12. GRB990123, OSSE observations
  13. GRB990123: NIR Observation
  14. GRB990123, ASCA X-ray observation of afterglow
  15. "GRB 990123: New BV Observations"
  16. GRB 990123 Optical Follow-Up
  17. GRB 990123: BATSE Observations
  18. GRB990123 Optical Observations
  19. GRB 990123: New Optical Observations, Decay Measure
  20. GRB 990123 Optical Follow-Up
  21. GRB 990123: Possible Gravitationally Lensed Burst?
  22. GRB990123, optical observation
  23. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  24. GRB990123, Optical observation
  25. GRB 990123: Optical Decay Slope
  26. GRB 990123 r-band photometry
  27. GRB 990123 Optical Follow-up
  28. GRB990123, early optical counterpart detection
  29. GRB990123 Optical Observation
  30. Possible identification of SN1999E with GRB980910
  31. Optical Observations of GRB 981220
  32. GRB 981226: radio variable
  33. GRB981220
  34. GRB981220, Correction to GCN 179
  35. GRB 981220 Optical observations
  36. GRB 981226 Optical Observations
  37. GRB 981220 and GRB 981226, optical observations
  38. GRB981226 Optical Observations
  39. GRB981226 BeppoSAX follow up
  40. GRB 981226
  41. GRB 981226 optical observations
  42. GRB981220 B, R and I band observations
  43. Optical Observations of GRB981226
  44. GRB 981220:Optical Observations
  45. GRB 981226 optical observations
  46. GRB 981220
  47. GRB 981220, radio observations
  48. GRB981220 I-band Observations
  49. GRB 981220
  50. GRB 980326/Host Galaxy
  51. GRB 981220: RXTE/ASM and BeppoSAX/GRBM results
  52. BeppoSAX NFI Observation of GRB980425
  53. GRB980329 R,I flux calibration and R,I,K upper limits
  54. GRB980425 Optical Follow-up
  55. GRB 980923 BATSE Observations
  56. SGR1900+14, BeppoSAX-GRBM observations
  57. GRB970508 optical observations
  58. GRB971214, association with a Galactic star?
  59. GRB980519, Optical Observations
  60. GRB980703 - BeppoSAX/GRBM detection
  61. GRB980703 optical photometry
  62. GRB 980703: BATSE Observations
  63. GRB980703 optical observations
  64. GRB980703: Radio transient
  65. GRB 980703: Spectrum of the proposed optical counterpart
  66. GRB980703 Transient Optical Follow-Up
  67. GRB980703: LOTIS observation at early times
  68. GRB980613 Optical Observations
  69. GRB980703 (I band observations)
  70. BeppoSAX NFI observations of GRB 980703
  71. GRB980519 observation report
  72. GRB980703 optical followup
  73. Radio observations of SGRs
  74. SGR1900+14 field optical observations
  75. GRB980613, optical observations
  76. GRB 980613: Optical transient and its host galaxy
  77. SGR1627-41, RXTE/ASM observations
  78. GRB 980613: Detection of the probable host galaxy
  79. Reduced error box of SGR 1627-41
  80. GRB 980613: BATSE Observations
  81. GRB 980613 Optical Observations
  82. GRB 980613 optical observations
  83. Discovery of a new SGR source, SGR1627-41
  84. GRB980613 Optical Observations
  85. GRB980613 observations from Palomar
  86. GRB 980613 optical/IR obs.
  87. GRB980613 Near Infra-Red Observations
  88. GRB971214 Secondary Standards
  89. GRB980519 Secondary Standards
  90. BATSE on-board GRB trigger change
  91. GRB 980519 Optical Observations
  92. GRB 980519
  93. GRB980519 optical observations
  94. GRB 980519 Optical Observations
  95. GRB980519 BATSE Observations
  96. GRB980519 Optical Observations
  97. GRB980519 Optical Observations
  98. GRB 980519 Optical Observations
  99. GRB980515, BeppoSAX IAUC to be submitted
  100. BSAX Observations of GRB980425 field

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