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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"

23093 results found.

  1. GRB 990627, radio observations
  2. Late-time HST/STIS Observation of GRB 990123
  3. Optical Observations of GRB 990506
  4. GRB990527 Optical Observations
  5. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  6. IPN error box for GRB990527
  7. Late Afterglows of GRBs 990510, 990123
  8. X-ray/GRB 1SAX J0835.9+5118, TNG V and R observations
  9. X-ray/GRB 1SAX J0835.9+5118, BATSE Observation
  10. GRB 990506 optical observation
  11. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  12. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  13. X-ray/GRB 1SAX J0835.9+5118, Optical Observation
  14. optical observation of the X-ray/GRB transient SAX J0835.9+5118
  15. GRB 990510: optical linear polarization
  16. GRB 990510: optical observations
  17. GRB990510, VI observations
  18. GRB 990506 R band observations
  19. GRB 990510: BATSE Observations
  20. GRB 990510 Optical Observations
  21. GRB 990510, BVI photometry
  22. GRB 990510 optical observations
  23. GRB 990510: BeppoSAX/GRBM observations
  24. GRB990510 optical observations
  25. GRB 990510 optical observations
  26. IPN localization of GRB990510
  27. GRB 990123, optical monitoring
  28. GRB 990506: BATSE Observations
  29. GRB 990506 optical observations
  30. GRB 990506, optical observations
  31. GRB990506 observation plan
  32. Refined IPN error box for GRB990506
  33. GRB 990506: Limits on the possible optical transient
  34. GRB 990506, optical observations
  35. GRB990506 Optical observations
  36. GRB990506 observation plan
  37. New IPN/RXTE error box for GRB990506
  38. IPN localization for GRB990506
  39. GRB 970228: Redshift and properties of the host galaxy
  40. IPN localization of GRB990427
  41. GRB980425 Optical observations of exponential decline at late time
  42. GRB990321 REFINED IPN ANNULUS
  43. GRB990323 PRECISE IPN POSITION
  44. GRB990321 IPN TRIANGULATION
  45. GRB 990316 Optical Observations
  46. GRB 990316 optical observations
  47. GRB990316 - Optical null results
  48. ASM/IPN error box for GRB 990308 (BATSE #7457)
  49. GRB990308 (Trig. 7457), optical observations
  50. GRB990308, Possible new SGR~0209+70
  51. GRB981220, IPN localization
  52. GRB 990123, Field Photometry
  53. GRB 990217 Optical Observations
  54. GRB 990217, radio observations
  55. GRB990217: BeppoSAX/GRBM data
  56. GRB990123 observations
  57. GRB990217 Optical observation
  58. GRB990123, Optical Observation
  59. GRB 990123: Discovery of the Probable Host Galaxy
  60. GRB 990123: Reduced HST Images
  61. GRB19990123 observations
  62. GRB 990123: BVRI standards in the field
  63. GRB 990123: Updated Keck Spectroscopy Results
  64. GRB981220, field photometry
  65. GRB 990123 NOT Spectrum Update
  66. GRB 990123: Publicly available reduced HST images
  67. GRB 990123: New Constraints on Possible Foreground Galaxies
  68. GRB990123, Probability of gravitational lensing
  69. GRB 990123: Detection of the IR Transient, and the Light Curve Fits
  70. GRB 990123: Correction to GCN 230 - C.A. Young added to author list
  71. GRB990123, OSSE observations
  72. GRB 990123: Strong MeV CGRO-COMPTEL detection now posted on WWW
  73. GRB990123, ASCA X-ray observation of afterglow
  74. GRB 990123 Optical Follow-Up
  75. GRB 990123: BATSE Observations
  76. GRB990123 IPN annulus
  77. GRB990123 Optical Observations
  78. GRB 990123 Spectroscopic Redshifts
  79. GRB 990123: New Optical Observations, Decay Measure
  80. GRB 990123 Optical Follow-Up
  81. GRB 990123: Possible Gravitationally Lensed Burst?
  82. GRB990123, optical observation
  83. GRB990123 optical observations
  84. GRB990123, Optical observation
  85. GRB 990123: Optical Decay Slope
  86. GRB990123 Optical Observation
  87. GRB990123, BeppoSAX-NFI X-ray afterglow detection
  88. GRB990123, refined SAX-WFC position
  89. Possible identification of SN1999E with GRB980910
  90. Optical Observations of GRB 981220
  91. GRB981220
  92. GRB981220, Optical Observations
  93. GRB 981220 Optical observations
  94. GRB 981226 Optical Observations
  95. GRB 980613: Spectroscopy of the host galaxy
  96. GRB981226 Optical Observations
  97. GRB981226 BeppoSAX follow up
  98. GRB 981226
  99. GRB981220 B, R and I band observations
  100. GRB981226, BeppoSAX-NFI follow-up

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