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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"

6403 results found.

  1. XRF 040916, optical follow-up
  2. GRB 040912: Optical Observations
  3. Optical observations of GRB/XRF 040912 = HETE 3557
  4. GRB040912 : Kiso Optical follow-up observation
  5. HETE 3557: Optical observations
  6. GRB040827: analysis of the XMM-Newton observation
  7. GRB 040827: 2nd epoch of Magellan K-band imaging
  8. GRB 040827: Detection of NIR afterglow
  9. GRB 040825: Optical observations
  10. GRB 040812: Second epoch CXO Observations
  11. CXO observation of GRB 040812
  12. GRB 040730, infrared observations
  13. GRB 040730: Optical observations
  14. XRF 040701, optical observations
  15. SGR 1806-20: no IR variability of the proposed counterparts
  16. SGR 1806-20, potential NIR counterpart
  17. GRB 040511: NIR observations with REM
  18. GRB 040511: Optical Observations
  19. GRB040422 : I-band follow-up observation at Lulin Observatory
  20. GRB 040403: Optical Observations
  21. GRB 040323, a dark GRB ?
  22. GRB 040323: a long GRB detected with INTEGRAL
  23. GRB040223: Deep NIR NTT data re-analysis
  24. GRB040228 : KISO optical follow-up observation
  25. GRB 040223: Deep NIR NTT observations
  26. GRB 040223 : Optical observation (non-detection)
  27. GRB 040223: REM IJK Observations
  28. GRB 040223 XMM-Newton observation ...
  29. GRB 031203 XMM-Newton observation
  30. GRB031203: ROSAT upper limits suggest XMM-S1 source as the transient
  31. XMM-Newton Observation of GRB031203
  32. GRB 031203: Deep NIR NTT & VLT observations
  33. XMM-Newton Observation of GRB031203
  34. GRB 031203: IR NTTobservations do not confirm REM detection
  35. GRB031203 : Optical Observation of Lulin Observatory
  36. GRB 031203: z ~ 10 or Fragmented Dust in the Circumburst Environment?
  37. GRB 031203: IR REM Observations
  38. GRB 031203 XMM-Newton observation
  39. IPN/HETE localization of GRB031109 (=H2917; large error box)
  40. GRB 031111: Optical observations
  41. Lulin optical follow-up observations of GRB031026
  42. GRB031026 : KISO optical follow-up observation
  43. XRF 030824: additional observations at CFHT
  44. XRF 030824: observations at CFHT
  45. Magellan Observations of GRB030725 (=H2779)
  46. XRF030723: Palomar observations and proposed counterpart
  47. XRF 030723, optical observations
  48. Konus-Wind detection of the bursts from SGR1806-20 region
  49. GRB030329: second XMM-Newton observation
  50. GRB030528(=H2724): X-ray Afterglow Identified in Second Epoch
  51. GRB 030528: Infrared Observations and the Proposed IR Counterpart
  52. GRB 030528: tentative NIR counterpart
  53. GRB 030416: Optical Observations
  54. GRB 030329: Optical limit (contemporaneous photography)
  55. GRB 030429: IR photometry with IRSF/SIRIUS
  56. GRB030501: TAROT candidate afterglow present in archival images
  57. GRB 030429: confirmation of afterglow candidate
  58. GRB 030329 Oprical observations in Rozhen observatory
  59. GRB030418: Kiso near infrared observations
  60. IPN triangulation of GRB030410 (annulus)
  61. GRB030329: Near Infrared Observations at Gunma
  62. GRB 030329 Optical observations
  63. GRB 030329, BVRI photometry
  64. GRB030329: Optical observations
  65. GRB030329, optical observation
  66. GRB030329, optical observation
  67. GRB 030329, BRI photometry
  68. GRB 030329: fading X-ray afterglow with RXTE
  69. GRB 030324: Optical and NIR Observations
  70. GRB030329: R and B observations
  71. GRB 030329: OT B and R photometry, decline rate
  72. GRB030329: Upper limits from recent and historical observations.
  73. GRB 030328: optical observations
  74. GRB 030328: OT photometry
  75. GRB030323: Detection on 2003/03/24
  76. GRB 030320: Optical Observations
  77. GRB 030324, optical observations
  78. GRB030226, addendum to GCN 1892
  79. GRB 030226 Optical observations
  80. GRB 030226: Ic Observations
  81. XMM-Newton observation of GRB030227
  82. GRB 030226: Confirmed decay index
  83. GRB030217: optical observations
  84. GRB 030204: Optical Observations
  85. GRB020819: Kiso R and I band observations
  86. GRB 030204, optical observations
  87. GRB030131: Kiso optical limit for corrected position
  88. GRB030131: Kiso Observations
  89. GRB 030115: Further IR observations with IRSF/SIRIUS
  90. GRB 030115: IR observations with IRSF/SIRIUS
  91. GRB 021219: OSN optical observations
  92. GRB021211: Kiso Observations
  93. GRB021204: Kiso Observations
  94. Chandra observation of the IPN error box of GRB021201 (short/hard)
  95. GRB021113: Kiso Observations
  96. Detection of activity from SGR 1900+14 with the RXTE/PCA
  97. GRB 021023: Curious K-band Source(s) Just Outside of IPN Localization
  98. GRB021004: High-resolution optical spectroscopy
  99. XRF 020903 spectrum
  100. GRB 021004 redshift

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