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Optical and Infrared Observations of Anomalous X-ray Pulsars

Martin Durant, Marten H. van Kerkwijk, Ferdi Hulleman
2004 Symposium - International astronomical union  
., van Kerkwijk, M. H., Kulkarni, S. R., 2003, A&A, submitted. Israel, G.  ...  H., Wilson-Hodge, C., Gurus, E., van der Klis, M., & Belloni,T. 2003, ApJ 587, 367 Thompson, C., Duncan, R. C., 1996 White, N. E., Angelini, L., Ebisawa, K., Tanaka, Y.  ... 
doi:10.1017/s0074180900181082 fatcat:ogqlvumj6ja67b6c3u75nxqgmm

Lithium Depletion of Nearby Young Stellar Associations

Erin Mentuch, Alexis Brandeker, Marten H. van Kerkwijk, Ray Jayawardhana, Peter H. Hauschildt
2008 Astrophysical Journal  
derived an age of 50 Myr by comparing the Hα emission strength of ABD members to members of the younger TUCHOR association, in addition to fitting its three M-type members to HR diagram isochrones.  ...  Known to be older than BPMG, but younger than the Pleiades, TUCHOR has an age of 20-40 Myr based on Hα measurements, X-ray luminosity, rotation and lithium abundances in comparison to other young clusters  ... 
doi:10.1086/592764 fatcat:s4ov2sdbqneqflq45732mxkioy

Multiwavelength Variability of the Magnetar 4U 0142+61

Martin Durant, Marten H. van Kerkwijk
2006 Astrophysical Journal  
The points have been de-extincted using A V = 3.5 (Durant & van Kerkwijk, 2006) .  ...  For example, whereas 1E 2259+586 and XTE J1810−197 showed correlated X-ray and infrared emission following outbursts (Tam et al. 2004; Gotthelf at al. 2004) , Durant & van Kerkwijk (2005) found that  ... 
doi:10.1086/507605 fatcat:lsd6lhiptrcspe4lhocktdb4xu

The Infrared Counterpart to the Magnetar 1RXS J170849.0−400910

Martin Durant, Marten H. van Kerkwijk
2006 Astrophysical Journal  
(Here we used F X = 6.4 × 10 −11 erg s −1 cm −2 [Woods & Thompson, 2004] and N H = 1.3 × 10 22 cm −2 [Durant & van Kerkwijk, 2006a] ).  ...  The first two groups are expected from our analysis of the run of reddening with distance in this direction (Durant & van Kerkwijk, 2006b) .  ... 
doi:10.1086/505740 fatcat:6pf75kgryvbhjdir7ux7zlbzri


Duy Cuong Nguyen, Alexander Scholz, Marten H. van Kerkwijk, Ray Jayawardhana, Alexis Brandeker
2009 Astrophysical Journal  
As proxies for the accretion rate, we use the H-alpha 10% width and the CaII-8662 line flux. We find that while the two quantities are correlated, their variability amplitude is not.  ...  Converted to accretion rates, the CaII fluxes indicate typical accretion rate changes of 0.35 dex, with 32% exceeding 0.5 dex, while H-alpha 10% width suggests changes of 0.65 dex, with 66% exceeding 0.5  ...  Next, the maximum flux level of Hα emission was measured with respect to this continuum level.  ... 
doi:10.1088/0004-637x/694/2/l153 fatcat:52oa2buih5cxnmoyk77k4bmfke

Interstellar Interferometry: Precise Curvature Measurement from Pulsar Secondary Spectra [article]

Daniel Baker, Walter Brisken, Marten H. van Kerkwijk, Robert Main, Ue-Li Pen, Tim Sprenger, Olaf Wucknitz
2021 arXiv   pre-print
Kerkwijk et al. ( 2011 ).  ...  Measuring inclinations is expected to be particularly interesting for certain black widow and redback systems which may have exceptionally high masses. van Kerkwijk et al. (2011) used light curve modelling  ... 
arXiv:2101.04646v2 fatcat:xrgchteyszfl3fsc3qatptg7iq

Distances to Anomalous X‐Ray Pulsars Using Red Clump Stars

Martin Durant, Marten H. van Kerkwijk
2006 Astrophysical Journal  
We also thank Bryan Gaensler for help with interpreting CO and H I data and for discussions about 1E 1048.1−5937, Manami Sasaki and Terrance Gaetz for discussing the case of CTB 109, and Tom Dame and Peter  ...  Despite the existance of a new estimate of reddening from Durant & van Kerkwijk (2006) , the value given was not very constraining.  ...  -The three extinction estimates with uncertainties are from measurements of edges in high-resolution X-ray spectra by Durant & Van Kerkwijk (2006) .  ... 
doi:10.1086/506380 fatcat:z44xmc7iqjdc7hndshhxklydoq

Kinematics of Crab Giant Pulses [article]

Akanksha Bij, Hsiu-Hsien Lin, Dongzi Li, Marten H. van Kerkwijk, Ue-Li Pen, Wenbin Lu, Robert Main, Jeffrey B. Peterson, Brendan Quine, Keith Vanderlinde
2021 arXiv   pre-print
Most promising may be those for which significant scattering has already been inferred, such as FRB 121102 ( Baseband ((van Kerkwijk et al. 2020) ), tempo2 (Hobbs et al. 2006) , numpy (Harris et al  ...  ., i), where the pulse is bright in only a sub-band of frequencies rather than throughout the band, while three others show 'banded' spectra (f , h, and j), with the bands spaced by ∼ 20 to ∼ 50 MHz.  ... 
arXiv:2105.08851v3 fatcat:eflmzklrsvfmjmcjngwrjle3fq


Varun B. Bhalerao, Marten H. van Kerkwijk, Fiona A. Harrison, Mansi M. Kasliwal, S. R. Kulkarni, Vikram R. Rana
2010 Astrophysical Journal  
Prominent bands (TiO, CaH) and lines (Hα, Na i) are marked.  ...  Figure 11 shows sections of the last epoch spectra around Hα and the Na i doublet at 8184/8195 Å.  ... 
doi:10.1088/0004-637x/721/1/412 fatcat:tuski5rmfvdhrb6bwwkoclc2nu

Profile changes associated with DM events in PSR J1713+0747 [article]

Fang Xi Lin, Hsiu-Hsien Lin, Jing Luo, Robert Main, James McKee, Ue-Li Pen, Dana Simard, Marten H. van Kerkwijk
2021 arXiv   pre-print
Propagation effects in the interstellar medium and intrinsic profile changes can cause variability in the timing of pulsars, which limits the accuracy of fundamental science done via pulsar timing. One of the best timing pulsars, PSR J1713+0747, has gone through two "dip" events in its dispersion measure time series. If these events reflect real changes in electron column density, they should lead to multiple imaging. We show that the events are are well-fit by an underdense corrugated sheet
more » ... el, and look for associated variability in the pulse profile using principal component analysis. We find that there are transient pulse profile variations, but they vary in concert with the dispersion measure, unlike what is expected from lensing due to a corrugated sheet. The change is consistent in shape across profiles from both the Greenbank and Arecibo radio observatories, and its amplitude appears to be achromatic across the 820 MHz, 1.4 GHz, and 2.3 GHz bands, again unlike expected from interference between lensed images. This result is puzzling. We note that some of the predicted lensing effects would need higher time and frequency resolution data than used in this analysis. Future events appear likely, and storing baseband data or keeping multiple time-frequency resolutions will allow more in-depth study of propagation effects and hence improvements to pulsar timing accuracy.
arXiv:2106.09851v1 fatcat:burwrulwjvghni4feo5agehoyi

Reconstructing the Guitar: Blowing Bubbles with a Pulsar Bow Shock Backflow

Marten H. van Kerkwijk, Ashleigh Ingle
2008 Astrophysical Journal  
The Guitar Nebula is an H-alpha nebula produced by the interaction of the relativistic wind of a very fast pulsar, PSR B2224+65, with the interstellar medium.  ...  With the sizes, the expected Hα photon rates are given by, n α,b = f α 4πR 2 b v b n H 0 4πd 2 = f α n H 0 ,b θ 2 b µ b d, (5) where f α is the number of Hα photons emitted per neutral particle before  ...  This Hα nebula has, as the name implies, a guitar-like shape, with a bright head, a faint neck, and a body consisting of two larger bubbles (see Fig. 1 ).  ... 
doi:10.1086/591792 fatcat:vgly26grerewxcw2my2vhrkdni

Accretion Disks around Young Stars: Lifetimes, Disk Locking, and Variability

Ray Jayawardhana, Jaime Coffey, Alexander Scholz, Alexis Brandeker, Marten H. van Kerkwijk
2006 Astrophysical Journal  
Based on Hα line profiles, along with a variety of other emission lines, we find clear evidence of on-going accretion in three out of 11 eta Cha stars and two out of 32 TW Hydrae members.  ...  We show Hα profiles for selected objects in Fig. 4 and 5.  ...  We examine the Hα variability of TWA 5A in detail in Sect. 6.  ... 
doi:10.1086/506171 fatcat:ibrxetuwhfapznmhbs5saiik74

Possible Optical Detection of the Anomalous X-Ray Pulsar CXOU J010043.1-721134

Martin Durant, Marten H. van Kerkwijk
2005 Astrophysical Journal  
Durant & van Kerkwijk, 2005) .  ...  It has been observed that infrared to X-ray flux ratios are similar for those AXPs with secure measurements (4U 0142+61, 1E 1048.1−5937 and 1E 2259+586; Durant & van Kerkwijk, 2005) .  ... 
doi:10.1086/432882 fatcat:qso57xjcvvc63niyvqcowdwewu

The Temperature and Cooling Age of t h e White-Dwarf Companion to the Millisecond Pulsar PSR B1855+09

Jon Bell, Marten van Kerkwijk, Vicky Kaspi, Shri Kulkarni
2000 International Astronomical Union Colloquium  
See van Kerkwijk et al. ApJ (submitted) for more details.  ...  For this binary, Gyr (Lorimer t Ӎ 7 PSR et al. 1995) , while from the surface temperature and gravity, as determined using optical spectroscopy ( K, T Ӎ 8500 eff ; van Kerkwijk, Bergeron, & Kulkarni  ...  This is somewhat larger than we have found for other fields (e.g., van Kerkwijk & Kulkarni 1999) , probably because in this crowded field there are residual problems with blending in the USNO-A2.0 positions  ... 
doi:10.1017/s025292110006084x fatcat:tk3i2ynh7rdsdizwmgyf4i6bri

The Broadband Spectrum and Infrared Variability of the Magnetar AXP 1E 1048.1−5937

Martin Durant, Marten H. van Kerkwijk
2005 Astrophysical Journal  
Hulleman, van Kerkwijk & Kulkarni (2004) suggest that values in the range A V = 2 . . . 6 are possible.  ...  Hulleman, van Kerkwijk & Kulkarni (2004) suggest that for 4U 0142+61, values of reddening as low as A V ≃ 2 are possible, based on the run of reddening with distance along the line of sight.  ... 
doi:10.1086/429714 fatcat:25gjgct2tvdaja7gk3yqrtpdai
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