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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"

37935 results found.

  1. IPN triangulation of GRB030228 (annulus)
  2. GRB030227, BVRcIc field photometry
  3. GRB030226, BVRcIc field calibration
  4. GRB 030227 optical afterglow
  5. 030302: NOT A GRB
  6. 030228: NOT A GRB
  7. GRB 030228, optical observations
  8. GRB 030226: Steep Decline
  9. GRB 030227: Confirmed Optical Afterglow (S1-A)
  10. GRB 030226: R band polarimetric observations
  11. GRB 030226: Optical observations
  12. GRB 030227: fading of candidate optical afterglow 'S1-A'
  13. GRB030227:Optical observations
  14. GRB 20030226: Upper limits from recent and historical observations
  15. GRB 030227, possible optical counterpart of XMM-Newton source
  16. GRB030227 - faint tentative OT candidate
  17. GRB 030226, optical observations
  18. GRB030227: Kiso optical observations
  19. GRB 030227: Kyoto optical observation
  20. GRB 030226, optical light curve
  21. GRB 030226 spectroscopy
  22. Possible break in the GRB 030226 light curve
  23. GRB 030226 : Predicted light curve
  24. IPN triangulation of GRB030225 (annulus)
  25. GRB 030226: Confirmed decay index
  26. GRB030226: ESI spectroscopy
  27. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  28. GRB 030226 simultaneous optical observations
  29. Two absorption systems in GRB 030226
  30. GRB 030226, optical observations
  31. GRB 030226 Optical Spectra and R,I,z' Imaging
  32. GRB 030226, optical observations
  33. GRB 030226: Optical afterglow
  34. GRB 030217: Optical Observations at 4, 5, and 6 Days
  35. IPN triangulation of GRB030223 (annulus)
  36. IPN triangulation of GRB030220 (annulus)
  37. GRB: Non-Referencing of GCN Circulars.
  38. IPN triangulation of GRB030218 (annulus)
  39. IPN triangulation of GRB030217 (small error box)
  40. IPN triangulation of GRB030215C (annulus)
  41. IPN triangulation of GRB030217 (annulus)
  42. IPN triangulation of GRB030216 (annulus)
  43. IPN triangulation of GRB030215A and GRB030215B (annuli)
  44. GRB030115, WSRT radio observations - correction to GCN 1864
  45. GRB 030131: marginal optical detection
  46. GRB030115, WSRT radio observations
  47. IPN triangulation of GRB030206 (annulus)
  48. IPN triangulation of GRB030208 (annulus)
  49. GRB 030204: Optical Observations
  50. GRB030204 field photometry
  51. GRB020819: Kiso R and I band observations
  52. GRB 030204: Correction to GCN 1856
  53. GRB 030115: Optical Observations
  54. GRB 030204, optical observations
  55. IPN triangulation of GRB030204 (small error box)
  56. IPN triangulation of GRB030202 (annulus)
  57. GRB 030131, optical observations
  58. GRB030131: Kiso optical limit for corrected position
  59. GRB030131: Optical limits for corrected position
  60. GRB 030131: afterglow candidate
  61. GRB 030115, late-time optical observations
  62. GRB030131: corrected INTEGRAL position
  63. Type Ic SN2003L (SN/GRB?), optical spectrum
  64. GRB030131: Kiso Observations
  65. GRB 020819: Host galaxy at Radio Position
  66. IPN triangulation of GRB030131 - CORRECTION
  67. GRB 020819: afterglow candidate
  68. IPN triangulation of GRB030131
  69. GRB 030131 optical observations
  70. GRB 030131 optical observations
  71. A long GRB detected by INTEGRAL
  72. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  73. Type Ic SN2003L (SN/GRB?) Radio Observations
  74. IPN triangulation of GRB030127 (annulus)
  75. GRB030115 submm upper limit
  76. IPN triangulation of GRB030119 (two large error boxes)
  77. GRB 030115: Further IR observations with IRSF/SIRIUS
  78. IPN triangulation of GRB030117 (two large error boxes)
  79. Publicizing GRB Discoveries - A Message from NASA HQ
  80. GRB 030115: Radio detection of IR candidate
  81. GRB 030115, simultaneous observations by BOOTES-1
  82. GRB 030115: IR observations with IRSF/SIRIUS
  83. IPN triangulation of GRB030115C (large error box)
  84. GRB030115: R-band counterpart of IR candidate
  85. GRB030115, afterglow candidate
  86. GRB 021211: R-band observations at late-time
  87. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  88. IPN triangulation of GRB030115B (small error box)
  89. GRB 030115 : Possible IR counterpart
  90. GRB 030115: Radio Observations
  91. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  92. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  93. IPN triangulation of GRB030115B (annulus)
  94. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  95. Distribution of INTEGRAL SPI-ACS triggers
  96. GRB030115: R-band observations at Asiago
  97. GRB030115: TAROT optical observations
  98. GRB 021211: VLT spectrum
  99. GRB 030115: APO Optical Observations
  100. GRB 030115, no optical candidate

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