J/MNRAS/439/354 Sources around Tycho's Supernova 1572 (Bedin+, 2014)
Improved Hubble Space Telescope proper motions for Tycho-G and other stars in
the remnant of Tycho's Supernova 1572.
Bedin L.R., Ruiz-Lapuente P., Gonzalez Hernandez J.I., Canal R.,
Filippenko A.V., Mendez J.
<Mon. Not. R. Astron. Soc., 439, 354-371 (2014)>
=2014MNRAS.439..354B 2014MNRAS.439..354B
ADC_Keywords: Supernova remnants ; Stars, double and multiple ;
Proper motions ; Radial velocities
Keywords: astrometry - binaries: close - supernovae: individual: SNR 1572
Abstract:
With archival and new Hubble Space Telescope observations, we
have refined the space-velocity measurements of the stars in the
central region of the remnant of Tycho's supernova (SN) 1572, one of
the historical Galactic Type Ia supernova remnants (SNRs). We derived
a proper motion for Tycho-G of
(pmRAcosDE;pmDE) J2000.0 =(-2.63;,-3.98)±(0.06;,0.04)[formal errors]
±(0.18;0.10)[expected errors]mas/yr. If the star were at the
distance of the SNR (taken here to be 2.83kpc), its velocity would be
Vb=-51±1.5km/s. We also reconstruct the binary orbit that Tycho-G
should have followed if it were the surviving companion of SN 1572. We
redetermine the Ni abundance of this star and compare it with new
abundance data from stars of the Galactic disc, finding that [Ni/Fe]
is about 1.7σ above the Galactic trend. From the high velocity
of Tycho-G perpendicular to the Galactic plane
(-90±3km/s≤Vb≤-45±1km/s, for the allowed range of distances to
the star), its metallicity and its Ni excess, we find the probability
of it being a chance interloper to be P≲0.00037 at most. The
projected rotational velocity of the star should be below current
observational limits. The projected position of Tycho-G is, within the
uncertainties, consistent with the centroid of the X-ray emission of
Tycho's SNR; moreover, its brightness is generally consistent with the
post-explosion evolution of the luminosity of an SN companion. Among
the other 23 stars having V<22mag and located within 42-arcsec from
the X-ray centroid, only 4 are at distances compatible with that of
the SNR, and none of them shows any peculiarity. Therefore, if even
Tycho-G is not the surviving companion of SN 1572, the absence of
other viable candidates does favour the merging of two white dwarfs as
the producer of the SN.
Description:
The observations used to derive the PM measurements presented here
come from HST programmes GO-9729, GO-10098 and GO-12469
(PI: Ruiz-Lapuente), which span ∼8yr. Data were collected with both
the WFC of the ACS and the Ultraviolet-Visual (UVIS) channel of the
Wide Field Camera 3 (WFC3). All of these images were taken with the
filter F555W, available for both cameras.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
catalog.dat 137 1148 Our catalogue for the sources in common with
those in P04 (related to Ruiz-Lapuente et al.,
2004Natur.431.1069R 2004Natur.431.1069R) (table 2 of the paper)
table3.dat 112 24 Data for the 24 stars with mV≤22mag, located
within 42 arcsec from the Xray centroid of
Tycho's SNR
fig3.fits 2880 156252 Stack of the deep WFC3/UVIS/F555W _flt images
from GO-12469 transformed into the reference
frame (TychoGF555WWCS.fits in the paper;
image of 15000x15000pix, scale=0.02arcsec/pix)
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Byte-by-byte Description of file: catalog.dat
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Bytes Format Units Label Explanations
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1- 4 I4 --- ID [1/1148] Sequential number
6- 14 F9.3 pix Xpos X position
16- 24 F9.3 pix Ypos Y position
26- 27 I2 h RAh Right ascension (J2000, Ep=2011.858)
29- 30 I2 min RAm Right ascension (J2000, Ep=2011.858)
32- 37 F6.3 s RAs Right ascension (J2000, Ep=2011.858)
39 A1 --- DE- Declination sign (J2000)
40- 41 I2 deg DEd Declination (J2000, Ep=2011.858)
43- 44 I2 arcmin DEm Declination (J2000, Ep=2011.858)
46- 50 F5.2 arcsec DEs Declination (J2000, Ep=2011.858)
52- 59 F8.3 mas/yr pmRA ?=99.990 Proper motion along RA (pmRA*cosDE)
63- 68 F6.3 mas/yr e_pmRA ?=99.990 rms uncertainty on pmRA
71- 77 F7.3 mas RAo ?=99.990 Correction to be applied to our
reference-frame RA at epoch 2011.858 (1)
81- 86 F6.3 mas e_RAo ?=99.990 rms uncertainty on RAo
89- 95 F7.3 mas/yr pmDE ?=99.990 Proper motion along DE
99-104 F6.3 mas/yr e_pmDE ?=99.990 rms uncertainty on pmDE
108-113 F6.3 mas DEo ?=99.990 Correction to be applied to our
reference-frame DE at epoch 2011.858
117-122 F6.3 mas e_DEo ?=99.990 rms uncertainty on DEo (1)
124 I1 --- ef [1/4] Number of epochs used
126-127 I2 --- Nu [0/72] number of neighbouring stars used
to derive the boresight corrections
129-134 A6 --- --- [Tycho-]
135-137 A3 --- Star P04 name (<[RCM2004] Tycho AN> in Simbad)
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Note (1): Note that in fitting the data, we let the positions at the reference
epoch float freely; consequently, DEo and RAo indicate the corrections to be
applied to our reference-frame positions at epoch 2011.858.
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- Star P04 name <[RCM2004] Tycho AN> in Simbad
4- 8 F5.2 mag Bmag ?=- B magnitude
10- 13 F4.2 mag e_Bmag ? rms uncertainty on Bmag
15- 19 F5.2 mag Vmag ?=- V magnitude
21- 24 F4.2 mag e_Vmag ? rms uncertainty on Vmag
26- 30 F5.2 mag Rmag ?=- R magnitude
32- 35 F4.2 mag e_Rmag ? rms uncertainty on Rmag
37- 41 F5.2 mas/yr pmb Proper motion perpendicular to the
Galactic plane
43- 46 F4.2 mas/yr e_pmb rms uncertainty on pmb
48- 49 A2 --- l_Dist [~≥< ] Limit flag on Dist
50- 54 F5.2 kpc Dist Distance
56- 58 F3.1 kpc e_Dist ? rms uncertainty on Dist
59 A1 --- n_Dist [-/] - for interval, / for second value
60 A1 --- l_Dist2 [~] Limit flag on Dist2
61- 64 F4.1 kpc Dist2 ? Upper value of distance when interval or
second distance value
66- 70 F5.1 km/s RV ?=- Radial velocity
72- 75 F4.1 km/s e_RV ? rms uncertainty on RV
77- 78 A2 --- l_VRA [~≥< ] Limit flag on VRA
79- 84 F6.1 km/s VRA Tangential velocity component along RA
86- 88 F3.1 km/s e_VRA ? rms uncertainty on VRA
89 A1 --- n_VRA [-/] - for interval, / for second value
90 A1 --- l_VRA2 [~] Limit flag on VRA2
91- 94 I4 km/s VRA2 ? Upper value of VRA when interval or
second VRA value
96- 97 A2 --- l_VDE [~≥< ] Limit flag on VDE
98-102 F5.1 km/s VDE Tangential velocity component along DE
104-107 F4.2 km/s e_VDE ? rms uncertainty on VDE
108 A1 --- n_VDE [-/] - for interval, / for second value
109 A1 --- l_VDE2 [~] Limit flag on VDE2
110-112 I3 km/s VDE2 ? Upper value of VDE when interval or
second VDE value
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Acknowledgements:
Luigi Rolly Bedin, luigi.bedin(at)oapd.inaf.it
(End) Patricia Vannier [CDS] 11-Dec-2014