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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').
  1. GRB 030115: Radio detection of IR candidate
  2. GRB 030115, simultaneous observations by BOOTES-1
  3. GRB 030115: IR observations with IRSF/SIRIUS
  4. IPN triangulation of GRB030115C (large error box)
  5. GRB030115: R-band counterpart of IR candidate
  6. GRB030115, afterglow candidate
  7. GRB 021211: R-band observations at late-time
  8. GRB030115: Optical Observations, Swiss Telescope at La Silla (ESO, Chile)
  9. IPN triangulation of GRB030115B (small error box)
  10. GRB 030115 : Possible IR counterpart
  11. GRB 030115: Radio Observations
  12. GRB030115 (=H2533): A Long GRB Localized by the HETE WXM and SXC
  13. Distribution of INTEGRAL SPI-ACS triggers for GRB bursts
  14. IPN triangulation of GRB030115B (annulus)
  15. ANNOUNCEMENT ON INTEGRAL GRB ALERTS
  16. Distribution of INTEGRAL SPI-ACS triggers
  17. GRB030115: R-band observations at Asiago
  18. GRB030115: TAROT optical observations
  19. GRB 021211: VLT spectrum
  20. GRB 030115: APO Optical Observations
  21. GRB 030115, no optical candidate
  22. GRB 030115, optical observations
  23. GRB 030115, optical candidate
  24. Possible GRB030113 seen by SPI ACS
  25. Probable GRB030112B seen by SPI ACS
  26. Probable GRB030112 seen by SPI ACS
  27. Information about where HETE will be pointing
  28. Possible GRB030111 seen by SPI ACS
  29. Possible GRB030110b seen by SPI ACS
  30. Possible GRB 030110 seen by SPI ACS
  31. IPN triangulation of GRB030109 (annulus)
  32. IPN triangulation of GRB030105 (large error box)
  33. IPN triangulation of GRB030102B (refined localization - portion of annulus)
  34. Possible GRB 20030109 seen by SPI ACS
  35. IPN triangulation of GRB030102A - correction to peak flux
  36. IPN triangulation of GRB030102B (portion of annulus)
  37. IPN triangulation of GRB030102A (large error box)
  38. Coronas-F -Wind triangulation of GRB030102
  39. Possible GRB20030107 seen by SPI-ACS
  40. Possible GRB 20030105 seen by SPI ACS
  41. IPN triangulation of GRB030102 (annulus)
  42. GRB on 20030102 seen by SPI-ACS
  43. VLT spectroscopy of the probable host of GRB 021211
  44. GRB on 20030101 seen by SPI-ACS
  45. IPN triangulation of GRB030101 (two large error boxes)
  46. GRB021226
  47. GRB 021211: Probable Host and Underlying Supernova
  48. GRB 021226 registration by Helicon/Coronas-F
  49. Probable GRB in INTEGRAL SPI-ACS
  50. IPN triangulation of GRB021223 (two large error boxes)
  51. GRB021211, radio observations
  52. GRB 021112: Evidence for Another Dark Optical Afterglow
  53. GRB 021219: OSN optical observations
  54. GRB021219: Radio Observations
  55. GRB021219, optical observations
  56. IPN triangulation of GRB021219 - CORRECTION
  57. IPN triangulation of GRB021219
  58. GRB021219, optical observation by MASTER
  59. GRB021219: Correction to GCN 1766
  60. GRB021219 refined position with INTEGRAL
  61. VLT spectra of GRB 021211 revisited
  62. GRB021219: a long GRB localized by INTEGRAL
  63. GRB021211: APO optical observations
  64. IPN detection of continued activity from SGR1806-20
  65. IPN triangulation of GRB021215 (large error box)
  66. IPN triangulation of GRB021214 (annulus)
  67. XRF 020903 : HST observations
  68. GRB 021201: Optical Observations
  69. GRB 021211, optical observations
  70. GRB 021211: CTIO observations
  71. GRB021211: Measurement of Early Time Afterglow
  72. VLT spectrum of GRB 021211
  73. IPN triangulation of GRB021211B (two large error boxes)
  74. GRB 021211: early break in light curve
  75. GRB021211, BVRI field photometry
  76. GRB021211: Optical observations in CrAO
  77. GRB 021211, IR observations
  78. GRB 021211, optical observations
  79. GRB 021211: Optical Observations
  80. GRB021211: Kiso Observations
  81. GRB021204: Kiso Observations
  82. GRB 021201, optical observations
  83. GRB 021211: Radio Observations
  84. GRB021211: Optical observations
  85. GRB 021201 (short/hard), NOT observations
  86. SUB-MM SEARCH FOR GRB 021211
  87. Chandra observation of the IPN error box of GRB021201 (short/hard)
  88. GRB 021211 Milagro GeV/TeV Observations
  89. GRB 021211, R- and I-band observations
  90. GRB021211 - Upper limits from recent and historical observations
  91. GRB021211, OT at 108 s
  92. GRB021211 (HETE2493), OT at 143 sec
  93. GRB 021204: I-band Observations
  94. GRB021211 (=H2493): A Bright, Long GRB Localized by HETE-2 in Near-Real Time
  95. HETE 2493: Optical observations
  96. HETE 2493: Optical observations
  97. HETE 2493: Optical candidate
  98. GRB 021204: Optical Observations at RIKEN
  99. GRB 021125: Radio Observations
  100. IPN triangulation of GRB021206 (small error box)

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