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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"

20562 results found.

  1. GRB 040228 Optical observations
  2. GRB 040223: Deep NIR NTT observations
  3. GRB 040223 : Optical observation (non-detection)
  4. GRB 040223, VLA observations
  5. GRB 040223: REM IJK Observations
  6. GRB031111, optical observations
  7. GRB031220: 2nd Chandra observation and X-ray afterglow candidate
  8. GRB031203: Chandra Observations
  9. GRB040106, follow-up radio observations
  10. SN 2003dh/GRB030329 late-time optical spectroscopy
  11. GRB040106, Radio Observations
  12. GRB040106, likely optical afterglow
  13. GRB040106: Second Epoch Optical Observations
  14. GRB 031220: Optical observations of Chandra X-ray sources
  15. GRB040106: optical observations with REM+ROSS
  16. GRB 040106: Optical observations
  17. GRB031220(=H2976): Observation with the Chandra X-ray Observatory
  18. GRB031220: Palomar Observations
  19. GRB 031203 I-band monitoring
  20. GRB 2974 follow-up observations
  21. GRB031203, improved XMM position
  22. GRB 031203: Discovery of a dust echo
  23. GRB 031203: SMARTS optical monitoring
  24. GRB 021203: A Normal GRB viewed far off axis?
  25. XMM-Newton Observations of GRB031203: Preliminary Images
  26. GRB 031203: Variable Radio Source
  27. GRB 031203: Magellan spectrum of possible GRB host
  28. GRB 031203: Optical/IR Astrometry
  29. GRB031203 K prime photometry: correction to galaxy coordinates
  30. GRB 031203: Deep NIR NTT & VLT observations
  31. GRB031203: K' Photometry of the likely GRB host
  32. GRB 031203: Radio detection
  33. GRB 031203: Further reports on December 4 observations
  34. GRB 031203: IR NTTobservations do not confirm REM detection
  35. GRB 031203: z ~ 10 or Fragmented Dust in the Circumburst Environment?
  36. GRB 031203: Apparent Spectral Break
  37. GRB 031203: IR REM Observations
  38. GRB031203: Optical Observations
  39. GRB 031203: Optical/IR SMARTS Observations
  40. GRB031111A, prompt optical observations
  41. GRB 031111, Radio observations
  42. GRB 031111: Optical observations
  43. GRB 031111, optical observations
  44. SN 2003jd (SN/GRB?) -- X-ray Observations
  45. GRB031026: 1.2mm upper limit with MAMBO at the IRAM 30m
  46. Lulin optical follow-up observations of GRB031026
  47. SN 2003jd (SN/GRB?), Radio Observations
  48. GRB 031026: Further Ic Observations
  49. GRB 031026 (=H2882): Evidence for High Redshift from Prompt
  50. Peculiar Type Ic SN 2003jd (SN/GRB?), optical spectrum
  51. GRB 031026: Ic Observations
  52. GRB030329: radio observations at RT-22 (CrAO)
  53. XRF 030824: additional observations at CFHT
  54. SGR 1806-20 bursts with INTEGRAL and IBAS announcement on Soft Gamma-Ray Repeaters
  55. XRF 030723: Subaru Optical Observations
  56. XRF 030824: observations at CFHT
  57. XRF 030723: Detection of the likely host galaxy
  58. GRB030913: Subaru Optical Observations
  59. GRB 030913: ROTSE-3c Optical Observations
  60. GRB030913, candidate afterglow observations
  61. GRB 030913, optical candidate
  62. GRB030913: AAVSO optical observations
  63. GRB 030913, BOOTES observations
  64. GRB030913 (=H2849): Confirmation of the Flight Localization
  65. GRB030913 (=H2849): TAROT Observations
  66. Magellan Observations of GRB030725 (=H2779)
  67. XRF 020427: Gemini-South Spectroscopic Observations of the Host
  68. XRF030824: Optical observations
  69. IBAS detection of bursts from SGR 1806-20
  70. Radio Observations of SGR1806-20
  71. INTEGRAL ToO OBSERVATIONS OF SGR1806-20: CALL FOR CORRELATED OBSERVATIONS
  72. XRF030824: Second-epoch Palomar observations
  73. XRF030824: optical observations
  74. GRB030823: optical observations
  75. GRB030823: Palomar observations
  76. XRF030824: Palomar observations
  77. RAPTOR observations of GRB030823
  78. Lulin follow-up observations of GRB030823
  79. GRB 030817 = H2808 TAROT optical observations
  80. SGR 1808-20 (=H2802): A Possible new SGR
  81. GRB 021206 Optical Observations
  82. XRF030723(=H2777): Chandra Fading X-ray Afterglow Confirmed
  83. XRF 030723: Detection of a rebrightening in the optical afterglow
  84. GRB030725: Optical observations
  85. GRB021206 optical counterpart upper limit
  86. XRF030723: Re-analysis of ROTSE-III early images
  87. XRF030723 (=H2777): Second Epoch Magellan Observations
  88. GRB 030725: optical observations.
  89. GRB030725, optical transient observations
  90. XRF030723 Radio Observations
  91. XRF 030723: confirmation of fading optical counterpart
  92. XRF030723(=H2777): Chandra Observations
  93. XRF 030723: VLT spectra
  94. Magellan Observations of XRF030723 (=H2777)
  95. GRB030723: Upper limits from historical observations
  96. GRB030725, possible optical transient
  97. XRF030723: Palomar observations and proposed counterpart
  98. XRF030723: optical observations
  99. XRF030723 (= H2777): Chandra Observations Scheduled
  100. XRF030723, ROTSE-III Early Observations

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