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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"

25041 results found.

  1. GRB19990123 observations
  2. GRB 990123: BVRI standards in the field
  3. GRB981220, field photometry
  4. GRB990123, Optical observation
  5. GRB990123, 15-GHz limits
  6. GRB 990123: New Constraints on Possible Foreground Galaxies
  7. GRB990123 Optical Observations
  8. GRB990123, Probability of gravitational lensing
  9. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  10. GRB990123, Preliminary Lens Search Results
  11. On the Lensing Interpretation of GRB 990123
  12. Search for Potential Images of GRB 990123
  13. Search for Potential Images of GRB 990123
  14. GRB990123, Optical BVRI Observations
  15. GRB 990123: near-infrared observations.
  16. GRB990123, OSSE observations
  17. GRB990123: NIR Observation
  18. GRB990123, ASCA X-ray observation of afterglow
  19. "GRB 990123: New BV Observations"
  20. GRB 990123 Optical Follow-Up
  21. GRB 990123: BATSE Observations
  22. GRB990123 Optical Observations
  23. GRB 990123: New Optical Observations, Decay Measure
  24. GRB 990123 Optical Follow-Up
  25. GRB 990123: Possible Gravitationally Lensed Burst?
  26. GRB990123, optical observation
  27. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  28. GRB990123, Optical observation
  29. GRB 990123: Optical Decay Slope
  30. GRB 990123 r-band photometry
  31. GRB 990123 Optical Follow-up
  32. GRB990123, early optical counterpart detection
  33. GRB990123 Optical Observation
  34. Possible identification of SN1999E with GRB980910
  35. Optical Observations of GRB 981220
  36. GRB 981226: radio variable
  37. GRB981220
  38. GRB981220, Correction to GCN 179
  39. GRB 981220 Optical observations
  40. GRB 981226 Optical Observations
  41. GRB 981220 and GRB 981226, optical observations
  42. GRB981226 Optical Observations
  43. GRB981226 BeppoSAX follow up
  44. GRB 981226
  45. GRB 981226 optical observations
  46. GRB981220 B, R and I band observations
  47. Optical Observations of GRB981226
  48. GRB 981220:Optical Observations
  49. GRB 981226 optical observations
  50. GRB 981220
  51. GRB 981220, radio observations
  52. GRB981220 I-band Observations
  53. GRB 981220
  54. GRB 980326/Host Galaxy
  55. GRB 981220: RXTE/ASM and BeppoSAX/GRBM results
  56. BeppoSAX NFI Observation of GRB980425
  57. GRB980329 R,I flux calibration and R,I,K upper limits
  58. GRB980425 Optical Follow-up
  59. GRB 980923 BATSE Observations
  60. SGR1900+14, BeppoSAX-GRBM observations
  61. GRB970508 optical observations
  62. GRB971214, association with a Galactic star?
  63. GRB980519, Optical Observations
  64. GRB980703 - BeppoSAX/GRBM detection
  65. GRB980703 optical photometry
  66. GRB 980703: BATSE Observations
  67. GRB980703 optical observations
  68. GRB980703: Radio transient
  69. GRB 980703: Spectrum of the proposed optical counterpart
  70. GRB980703 Transient Optical Follow-Up
  71. GRB980703: LOTIS observation at early times
  72. GRB980613 Optical Observations
  73. GRB980703 (I band observations)
  74. BeppoSAX NFI observations of GRB 980703
  75. GRB980519 observation report
  76. GRB980703 optical followup
  77. Radio observations of SGRs
  78. SGR1900+14 field optical observations
  79. GRB980613, optical observations
  80. GRB 980613: Optical transient and its host galaxy
  81. SGR1627-41, RXTE/ASM observations
  82. GRB 980613: Detection of the probable host galaxy
  83. Reduced error box of SGR 1627-41
  84. GRB 980613: BATSE Observations
  85. GRB 980613 Optical Observations
  86. GRB 980613 optical observations
  87. Discovery of a new SGR source, SGR1627-41
  88. GRB980613 Optical Observations
  89. GRB980613 observations from Palomar
  90. GRB 980613 optical/IR obs.
  91. GRB980613 Near Infra-Red Observations
  92. GRB971214 Secondary Standards
  93. GRB980519 Secondary Standards
  94. BATSE on-board GRB trigger change
  95. GRB 980519 Optical Observations
  96. GRB 980519
  97. GRB980519 optical observations
  98. GRB 980519 Optical Observations
  99. GRB980519 BATSE Observations
  100. GRB980519 Optical Observations

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