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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"

36141 results found.

  1. GRB030227: Kiso optical upper limit
  2. IPN triangulation of GRB030301 (annulus)
  3. IPN triangulation of GRB030228 (annulus)
  4. GRB030227, BVRcIc field photometry
  5. GRB030226, BVRcIc field calibration
  6. GRB 030227 optical afterglow
  7. 030302: NOT A GRB
  8. 030228: NOT A GRB
  9. GRB 030228, optical observations
  10. GRB 030226: Steep Decline
  11. GRB 030227: Confirmed Optical Afterglow (S1-A)
  12. GRB 030226: R band polarimetric observations
  13. GRB 030226: Optical observations
  14. GRB 030227: fading of candidate optical afterglow 'S1-A'
  15. GRB030227:Optical observations
  16. GRB 20030226: Upper limits from recent and historical observations
  17. GRB 030227, possible optical counterpart of XMM-Newton source
  18. GRB030227 - faint tentative OT candidate
  19. GRB 030226, optical observations
  20. GRB030227: Kiso optical observations
  21. GRB 030227: Kyoto optical observation
  22. GRB 030226, optical light curve
  23. GRB 030226 spectroscopy
  24. Possible break in the GRB 030226 light curve
  25. GRB 030226 : Predicted light curve
  26. IPN triangulation of GRB030225 (annulus)
  27. GRB 030226: Confirmed decay index
  28. GRB030226: ESI spectroscopy
  29. GRB030226 (=U10893): A Long GRB Localized by the HETE WXM and SXC
  30. GRB 030226 simultaneous optical observations
  31. Two absorption systems in GRB 030226
  32. GRB 030226, optical observations
  33. GRB 030226 Optical Spectra and R,I,z' Imaging
  34. GRB 030226, optical observations
  35. GRB 030226: Optical afterglow
  36. GRB 030217: Optical Observations at 4, 5, and 6 Days
  37. IPN triangulation of GRB030223 (annulus)
  38. IPN triangulation of GRB030220 (annulus)
  39. GRB: Non-Referencing of GCN Circulars.
  40. IPN triangulation of GRB030218 (annulus)
  41. IPN triangulation of GRB030217 (small error box)
  42. IPN triangulation of GRB030215C (annulus)
  43. IPN triangulation of GRB030217 (annulus)
  44. IPN triangulation of GRB030216 (annulus)
  45. IPN triangulation of GRB030215A and GRB030215B (annuli)
  46. GRB030115, WSRT radio observations - correction to GCN 1864
  47. GRB 030131: marginal optical detection
  48. GRB030115, WSRT radio observations
  49. IPN triangulation of GRB030206 (annulus)
  50. IPN triangulation of GRB030208 (annulus)
  51. GRB 030204: Optical Observations
  52. GRB030204 field photometry
  53. GRB020819: Kiso R and I band observations
  54. GRB 030204: Correction to GCN 1856
  55. GRB 030115: Optical Observations
  56. GRB 030204, optical observations
  57. IPN triangulation of GRB030204 (small error box)
  58. IPN triangulation of GRB030202 (annulus)
  59. GRB 030131, optical observations
  60. GRB030131: Kiso optical limit for corrected position
  61. GRB030131: Optical limits for corrected position
  62. GRB 030131: afterglow candidate
  63. GRB 030115, late-time optical observations
  64. GRB030131: corrected INTEGRAL position
  65. Type Ic SN2003L (SN/GRB?), optical spectrum
  66. GRB030131: Kiso Observations
  67. GRB 020819: Host galaxy at Radio Position
  68. IPN triangulation of GRB030131 - CORRECTION
  69. GRB 020819: afterglow candidate
  70. IPN triangulation of GRB030131
  71. GRB 030131 optical observations
  72. GRB 030131 optical observations
  73. A long GRB detected by INTEGRAL
  74. GRB030115: 1.2 mm upper limits with MAMBO @ IRAM 30m
  75. Type Ic SN2003L (SN/GRB?) Radio Observations
  76. IPN triangulation of GRB030127 (annulus)
  77. GRB030115 submm upper limit
  78. IPN triangulation of GRB030119 (two large error boxes)
  79. GRB 030115: Further IR observations with IRSF/SIRIUS
  80. IPN triangulation of GRB030117 (two large error boxes)
  81. Publicizing GRB Discoveries - A Message from NASA HQ
  82. GRB 030115: Radio detection of IR candidate
  83. GRB 030115, simultaneous observations by BOOTES-1
  84. GRB 030115: IR observations with IRSF/SIRIUS
  85. IPN triangulation of GRB030115C (large error box)
  86. GRB030115: R-band counterpart of IR candidate
  87. GRB030115, afterglow candidate
  88. GRB 021211: R-band observations at late-time
  89. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  90. IPN triangulation of GRB030115B (small error box)
  91. GRB 030115 : Possible IR counterpart
  92. GRB 030115: Radio Observations
  93. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  94. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  95. IPN triangulation of GRB030115B (annulus)
  96. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  97. Distribution of INTEGRAL SPI-ACS triggers
  98. GRB030115: R-band observations at Asiago
  99. GRB030115: TAROT optical observations
  100. GRB 021211: VLT spectrum

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