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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"

21788 results found.

  1. GRB 990123: Continued Radio Observations
  2. GRB990123, Preliminary Lens Search Results
  3. On the Lensing Interpretation of GRB 990123
  4. Search for Potential Images of GRB 990123
  5. GRB990123, Optical BVRI Observations
  6. GRB 990123: near-infrared observations.
  7. GRB990123, OSSE observations
  8. GRB990123: NIR Observation
  9. "GRB 990123: New BV Observations"
  10. GRB 990123 Optical Follow-Up
  11. GRB 990123; Addendum to GCN 223
  12. GRB 990123: BATSE Observations
  13. GRB 990123 Keck Spectrum update
  14. GRB 990123 : Multiple and Distorted Images of the Host Galaxy?
  15. GRB990123 Optical Observations
  16. GRB 990123 Spectroscopic Redshifts
  17. GRB 990123: New Optical Observations, Decay Measure
  18. GRB 990123 Optical Follow-Up
  19. GRB 990123: Possible Gravitationally Lensed Burst?
  20. GRB990123, optical observation
  21. GRB 990123 optical observations
  22. GRB 990123: Pre-Burst Detection of an Apparent Host Galaxy
  23. GRB 990123 radio observations
  24. GRB 990123, new radio source
  25. GRB990123 optical observations
  26. GRB990123, Optical observation
  27. GRB 990123 Optical Follow-up
  28. GRB 990123: Bright New Source, Possible Optical Transient
  29. GRB 990123, Radio observations
  30. SN 1999E & GRB 980919
  31. Possible identification of SN1999E with GRB980910
  32. Optical Observations of GRB 981220
  33. GRB 981226: radio variable
  34. GRB981220
  35. GRB981220, Correction to GCN 179
  36. GRB981220, Optical Observations
  37. GRB 981220 Optical observations
  38. GRB 981226 Optical Observations
  39. GRB 980613: Spectroscopy of the host galaxy
  40. GRB981226, sub-millimeter observations
  41. GRB981220, sub-millimeter observations
  42. GRB 981220 and GRB 981226, optical observations
  43. GRB981226 Optical Observations
  44. GRB 981226 radio observations
  45. GRB 981226
  46. GRB 981226 optical observations
  47. radio observations of GRB 981226
  48. GRB981220 B, R and I band observations
  49. Optical Observations of GRB981226
  50. GRB 981220:Optical Observations
  51. GRB 981220 optical R and I observations
  52. GRB981226, BeppoSAX Christmas GRB
  53. GRB 981226 - Infrared Observations
  54. GRB 981226 optical observations
  55. GRB 981220
  56. GRB 981220, radio observations
  57. GRB 981220, radio observations
  58. GRB981220 I-band Observations
  59. GRB981220 Optical Observations
  60. GRB 981220
  61. GRB 981220 Optical Observations
  62. GRB 981220, optical observations
  63. GRB 980326/Host Galaxy
  64. GRB980329 R,I flux calibration and R,I,K upper limits
  65. GRB980425 Optical Follow-up
  66. GRB980425: X-ray revised positions
  67. GRB 980923 BATSE Observations
  68. SGR1900+14, BeppoSAX-GRBM observations
  69. GRB980703 Very Long Baseline Interferometry
  70. GRB970508 optical observations
  71. GRB971214, association with a Galactic star?
  72. Optical Observations of the Host Galaxy of GRB 980519
  73. GRB980519, Optical Observations
  74. GRB980703, Host galaxy multicolor photometry
  75. GRB 980703 (NFI observations)
  76. GRB980703 optical photometry
  77. GRB 980703: BATSE Observations
  78. GRB980703 optical observations
  79. GRB980703: Radio transient
  80. GRB980703 H-band Observations
  81. GRB 980703: Spectrum of the proposed optical counterpart
  82. GRB980703: Spectrum of the proposed optical counterpart
  83. GRB980613 Optical Observations
  84. GRB980703 (I band observations)
  85. GRB 980703 H-band Observations
  86. GRB980703 (optical R observations)
  87. GRB980703: radio source/optical transient
  88. BeppoSAX NFI observations of GRB 980703
  89. Radio observations of SGRs
  90. SGR1900+14 field optical observations
  91. GRB 980613 Near-IR observations
  92. GRB980613, optical observations
  93. GRB 980613: Optical transient and its host galaxy
  94. SGR1627-41, RXTE/ASM observations
  95. GRB 980613: Detection of the probable host galaxy
  96. Reduced error box of SGR 1627-41
  97. GRB 980613: BATSE Observations
  98. GRB 980613 Optical Observations
  99. GRB 980613 optical observations
  100. Discovery of a new SGR source, SGR1627-41

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