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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"

35940 results found.

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

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