I am trying to plot a light curve at a certain interval and set my kernel to read the file starting at a certain header. When I print my x and y values, they match up to the interval I set, but once I plot, it plots the WHOLE dataset as if I never restricted it with a skip_header at all, which is confusing because this is from an older routine I’ve done, and I’ve never had this problem before with any other datasets I’ve used.

This dataset in particular is very large (over 45000 lines), and I’m trying to look at the last 11000 lines or so for a specific period of time, so while I can’t put in all of the data, I can try and put in as many datapoints as possible from where I had wanted to start and some from the end so that there is something to work with. The first column is the time of observation (in MJD), the second column is the flux of the object and the third column is the error of the second column. I had set the skip_header in order to look at an interval of intensely monitored data (hence why there’s a lot of time stamps that are almost identical) from 56955 – 59110:

56955.249057806606 2.225637 2.066504

56955.24917573113 2.906579 0.5933052

56955.24929365566 3.430041 0.6559768

56955.24941158019 1.996177 0.5362438

56955.24952950472 3.055742 0.6702293

56955.24964742924 2.807112 0.6557623

56955.24976535377 2.723114 0.5942342

56955.2498832783 2.579723 0.5768454

56955.25000120283 1.994163 0.5260279

56955.25011912736 2.826056 0.6116026

57151.561321957546 3.461871 0.645721

57151.561439882076 2.933483 0.6083286

57151.561557806606 3.051795 0.619824

57151.56167573113 3.264719 0.6062458

57151.56179365566 4.166972 0.6850498

57151.56191158019 2.823483 0.5983652

57151.56202950472 5.528487 0.814224

57151.56214742924 2.896889 0.5942114

57151.56226535377 4.507289 0.7126694

57151.5623832783 2.866986 0.6138276

57151.56250120283 2.785882 0.5837799

57151.56261912736 3.268119 0.6068772

57151.562737051885 3.121862 0.6151329

57151.562854976415 3.651836 0.6816578

57151.562972900945 3.233772 0.62522

57151.56309082547 3.153281 0.5959166

57151.56320875 2.79295 0.6177107

57151.56332667453 2.815265 0.5630551

57151.56344459906 2.751948 0.6028816

57151.56356252359 3.306673 0.6211404

57151.56368044811 2.220478 0.5261355

57151.56379837264 3.480417 0.6537772

57184.08844459906 3.274329 0.6092318

57184.08856252358 3.057429 0.5896085

57184.08868044811 3.142311 0.5835152

57184.08879837264 3.057604 0.5896422

57184.08891629717 2.623944 0.5483238

57184.089034221695 2.600297 0.5307854

57184.089152146225 3.575541 0.622425

57184.089270070755 2.742214 0.6287372

57184.089387995286 3.081095 0.6054505

57184.08950591981 1.672518 0.462543

57184.08962384434 3.490993 0.6281997

57184.08974176887 2.417206 0.6000872

57184.0898596934 2.322826 0.5333252

57184.08997761793 3.05768 0.5896569

57184.09009554245 2.925466 0.5630085

57184.09021346698 2.803018 0.6075559

57184.09033139151 2.600508 0.5308284

57184.090449316034 2.525404 0.6097533

57184.090567240564 4.44222 0.6937625

57184.090685165094 1.804648 0.4946223

57184.090803089624 2.70888 0.5417781

57184.090921014154 2.106017 0.5108127

57184.09103893868 2.43104 0.5441894

57184.09115686321 3.057709 0.5896624

57184.09127478774 2.167223 0.4846072

57184.09139271226 2.21443 0.5221925

57184.09151063679 4.307299 0.6897239

57184.09162856132 2.430778 0.5182454

57184.09174648585 3.274226 0.6092125

57184.09186441038 2.817077 0.5524765

57184.0919823349 2.732421 0.5589527

57184.09210025943 3.05757 0.5896355

57184.09221818396 2.430948 0.5441689

57184.09233610849 5.309473 0.7585018

57184.092454033016 1.173819 0.5352785

57184.092571957546 2.756094 0.575641

57184.092689882076 2.539575 0.5549115

57184.092807806606 4.249719 0.6905623

…

58966.50577935141 1.754738 0.5373108

58966.5069585967 2.186991 0.5471897

58966.50813784198 1.130976 0.4545428

58966.509317087264 1.651608 0.5551976

58966.51049633254 1.894271 0.5566368

58966.51167557783 2.40661 0.5842662

58971.8819585967 0.6648926 0.3151302

58971.88313784198 1.057266 0.256631

58971.884317087264 1.293281 0.2893841

58971.88549633254 1.056862 0.2645827

58971.88667557783 1.264739 0.2830219

58971.887854823115 1.350237 0.2949098

58971.889034068394 0.9227211 0.2712489

58971.89021331368 0.6526145 0.2191811

58971.89139255896 0.9170059 0.2370399

58971.892571804245 1.618029 0.3175093

58971.89375104953 1.439235 0.3002796

58971.89493029481 0.8620246 0.2895116

58980.55412840802 3.079561 1.034459

58980.5553076533 1.657865 0.5307714

58980.55648689858 2.245098 0.5801354

58980.55766614387 1.904343 0.5831209

58980.558845389154 2.063941 0.5334636

58980.56002463443 2.942607 0.6278495

58980.56120387972 1.073781 0.4315559

58980.562383125 1.800799 0.5762376

58980.563562370284 1.042554 0.4526092

58980.56474161557 1.131361 0.4547821

58980.56592086085 1.348874 0.5069342

58980.567100106135 1.454402 0.5465938

58980.56827935141 2.005936 0.5900149

58980.5694585967 2.31635 0.5623149

58980.57063784198 1.016554 0.7287736

58987.07417557783 0.9628347 0.2946667

58987.075354823115 1.047415 0.2187034

58987.076534068394 0.9119756 0.2041557

58987.07771331368 2.5208 0.8471503

58987.07889255896 1.110273 0.797823

58987.080071804245 1.28724 1.938599

58987.34304350236 1.051434 0.2716978

58987.34422274764 0.9936518 0.2343108

58987.34540199293 0.663515 0.2125841

58987.346581238206 1.487886 0.2866216

58987.34776048349 1.316436 0.2808193

58987.34893972877 1.81836 0.3971744

58987.35011897406 1.254957 0.2619059

58987.35129821934 1.972095 0.6993931

58987.35365670991 1.715693 1.032851

58987.354835955186 2.115329 0.7106273

58987.35601520047 1.017249 0.3114874

58987.35719444575 3.283559 1.424081

58987.35837369104 2.695172 1.278698

58987.35955293632 1.945537 1.171511

59005.950354823115 2.457725 1.163689

59005.951534068394 3.043288 1.143221

59005.95271331368 2.366545 1.026372

59005.95389255896 1.926578 0.9129619

59005.955071804245 2.354125 1.019919

59005.95625104953 2.080575 0.9851156

59005.95743029481 2.521668 1.012959

59005.958609540095 4.456445 1.42578

59005.959788785374 5.528537 1.38302

59005.96096803066 5.901176 1.431893

59005.962147275946 4.452185 1.308231

59005.963326521225 2.271442 0.984378

59005.96450576651 2.593893 0.975126

59005.96568501179 3.112013 1.04498

59005.966864257076 5.040055 1.302375

59005.96804350236 3.548844 1.256438

59006.01639255896 0.1889598 0.0758722

59006.017571804245 0.9539176 0.3377603

59006.01875104953 1.089439 0.4376564

59006.01993029481 1.804744 0.5523254

59006.021109540095 1.722343 0.5792394

59006.022288785374 1.61273 0.541734

59006.02346803066 1.729053 0.5530951

59006.024647275946 2.21328 0.5534554

59006.025826521225 2.235688 0.559241

59006.02700576651 1.940165 0.5700822

59006.02818501179 3.576312 0.715561

59006.029364257076 2.040711 0.5273219

59006.03054350236 1.532922 0.5436429

59006.03172274764 3.197589 0.6529181

59006.03290199293 2.638396 0.6057053

59006.034081238206 2.946389 0.6433144

59006.03526048349 1.908081 0.5840286

59006.083609540095 4.845532 1.627224

59006.084788785374 2.652127 0.6630784

59006.08596803066 1.676968 0.5940136

59006.087147275946 1.806198 0.5780618

59006.088326521225 2.051368 0.628334

59006.08950576651 3.026706 0.6950729

59006.09068501179 1.666243 0.55966

59006.091864257076 1.835313 0.5873797

59006.09304350236 2.168168 0.6643145

59006.09422274764 3.275818 0.7520134

59006.09540199293 2.879874 0.6791745

59006.096581238206 1.117225 0.4843119

59006.09776048349 1.80344 0.6062369

59006.09893972877 5.281922 0.964704

59006.10011897406 1.165037 0.5051103

59006.10129821934 3.953659 0.8433538

59006.10247746462 2.705614 0.7952228

59006.149647275946 3.686483 1.597388

59006.150826521225 2.188352 0.5652736

59006.15200576651 3.377672 0.7048876

59006.15318501179 3.6791 0.7359723

59006.154364257076 2.291994 0.5735082

59006.15554350236 2.601798 0.6510282

59006.15672274764 2.110224 0.5453274

59006.15790199293 3.52231 0.7198028

59006.159081238206 2.170314 0.5606626

59006.16026048349 3.474165 0.7247801

59006.16143972877 3.062065 0.6851414

59006.16261897406 3.136759 0.6691918

59006.16379821934 1.60031 0.5380025

59006.16497746462 2.681267 0.6708045

59006.16615670991 3.37432 0.7041485

59006.167335955186 1.162702 0.4673519

59006.16851520047 1.013747 0.4397691

59006.16969444575 2.966131 1.285436

59006.21804350236 2.024002 1.067142

59006.21922274764 4.568729 1.534547

59006.22040199293 3.165954 1.272088

59006.221581238206 4.237229 1.423462

59006.22276048349 3.005121 1.30295

59006.22393972877 2.382994 1.1304

59006.22511897406 4.457604 1.496137

59006.22629821934 2.668072 1.072038

59006.22747746462 3.044263 1.223039

59006.22865670991 3.355417 1.260333

59006.229835955186 2.591919 1.041112

59006.23101520047 3.592251 1.350341

59006.23219444575 2.005093 1.057362

59006.23337369104 1.934918 1.019356

59006.23455293632 2.846426 1.143272

59006.2357321816 1.159595 0.8324305

59006.23691142689 2.924155 2.098018

59006.28526048349 3.57719 1.201509

59006.28643972877 3.926041 0.7293754

59006.28761897406 2.339945 0.5679554

59006.28879821934 2.507434 0.591222

59006.28997746462 2.732702 0.6114095

59006.29115670991 2.448398 0.5778043

59006.292335955186 3.609849 0.6950849

59006.29351520047 2.486035 0.6034146

59006.29469444575 3.091182 0.644885

59006.29587369104 2.261428 0.5656795

59006.29705293632 1.977666 0.5813087

59006.2982321816 2.803351 0.6271753

59006.29941142689 2.294421 0.5568204

59006.30059067217 2.223968 0.5396812

59006.30176991745 2.714541 0.6071876

59006.30294916274 2.268873 0.5507894

59006.30412840802 2.309407 1.093666

59006.63667557783 2.470434 0.9284391

59006.637854823115 2.327981 0.5822504

59006.639034068394 2.327025 0.6840961

59006.64021331368 2.751391 0.6317564

59006.64139255896 2.131856 0.5509151

59006.642571804245 3.120302 0.6813228

59006.64375104953 2.941339 0.6752878

59006.64493029481 2.230671 0.5580754

59006.646109540095 3.084072 0.7718636

59006.82299633254 0.5579632 0.8380607

59006.82417557783 2.001342 0.4087262

59006.825354823115 2.240355 0.4237761

59006.826534068394 1.695472 0.3702841

59006.82771331368 1.409272 0.3422467

59006.82889255896 3.151832 0.5114559

59006.830071804245 1.729261 0.3776329

59006.83125104953 3.119518 0.9548466

59006.89375104953 2.530131 0.7745616

59006.89493029481 4.21794 0.7578832

59006.896109540095 4.320116 0.7892219

59006.897288785374 4.127552 0.7802157

59006.89846803066 2.374419 0.5601022

59006.899647275946 4.752351 0.8538708

59006.900826521225 3.416019 0.7125719

59006.90200576651 2.133289 0.5516762

59006.96096803066 10.34151 7.416362

59006.962147275946 3.583725 3.332487

59006.963326521225 16.79554 8.84984

59006.96450576651 10.42674 7.477483

59006.96568501179 11.52099 8.262221

59006.966864257076 5.543301 5.154687

59006.96804350236 9.320571 8.653817

59006.96922274764 19.83254 18.45142

59006.971581238206 7.538471 7.006477

59009.31474161557 3.464492 2.085111

59009.31592086085 1.868892 0.9855589

59009.317100106135 2.730272 1.097784

59009.31827935141 2.471687 1.072739

59009.3194585967 1.36249 0.820633

59009.32063784198 2.322338 1.100688

59009.321817087264 2.446578 1.060277

59009.32299633254 3.823443 1.437247

59009.32417557783 2.539448 1.101312

59009.325354823115 3.413683 1.282931

59009.326534068394 4.353062 1.393052

59009.32771331368 5.131232 3.681547

59101.50342086085 2.856692 0.6935412

59101.504600106135 2.71897 0.6600548

59101.50577935141 3.140092 0.6858205

59101.5069585967 2.793892 0.6417556

59101.50813784198 2.48059 0.6205522

59101.509317087264 3.294646 0.7194869

59101.51049633254 3.17599 0.6934885

59101.51167557783 2.491026 0.6233154

59101.512854823115 4.353469 0.8230349

59101.514034068394 1.845499 1.71612

59103.72393972877 2.230527 0.5123628

59103.72511897406 2.556621 0.4388096

59103.72629821934 2.226284 0.4068094

59103.72747746462 2.04568 0.3939903

59103.72865670991 2.001833 0.3854967

59103.729835955186 2.609824 0.441313

59103.73101520047 2.533585 0.4412917

59103.73219444575 2.271652 0.4150048

59103.73337369104 0.8394531 0.5060697

59104.792335955186 3.112703 0.5051742

59104.79351520047 2.446651 0.4398435

59104.79469444575 2.236333 0.4307367

59104.79587369104 2.715993 0.4730386

59104.79705293632 2.681876 0.4674111

59104.7982321816 2.856258 0.476382

59104.79941142689 2.899498 0.4902721

59104.80059067217 2.464417 0.4502209

59104.80176991745 2.338096 0.4420473

59104.80294916274 2.527087 0.4616175

59104.80412840802 2.834575 0.4863211

59104.8053076533 2.739051 0.4771781

59104.80648689858 1.767242 0.5658772

59106.59540199293 2.56547 0.4765565

59106.596581238206 1.898414 0.3878809

59106.59776048349 3.102969 0.4908226

59106.59893972877 2.767867 0.4615829

59106.60011897406 1.946241 0.3896038

59106.60129821934 2.517643 0.4452874

59106.60247746462 2.047855 0.4098381

59110.767571804245 14.23822 8.571443

59110.76875104953 34.5416 32.15226

59110.771109540095 10.49669 5.52988

59110.772288785374 38.72036 23.30975

59110.77346803066 16.28188 7.707895

59110.77700576651 6.871766 4.93134

from astropy.io import fits, ascii
import numpy as np
from astropy.table import Table
import pandas as pd
import scipy as sp
from astropy.time import Time
from astropy.timeseries import LombScargle
from astropy.timeseries import TimeSeries
from celerite import GP
import matplotlib.pyplot as plt
# test run with new files
data = np.genfromtxt('3C273_XRT_mjd.txt', skip_header = 34985)
x = data[:,0]
print(x)
y = data[:,1]
dy = data[:,2]
num = len(x)
print('Number of data points:', num)
print('Start MJD:', x[0])
print('End MJD:', x[num - 1])
# plotting initial light curve for 3c 273
plt.subplots(1,1, figsize=(12,8))
plt.scatter(x, y)
plt.xlabel('Time (MJD)')
plt.ylabel('Flux')
plt.title('3C 273 XRT initial LC')
plt.show()

I had created a new file converting the times originally found from seconds to MJD, thinking maybe the file wasn’t organized in chronological order, but this did nothing to solve the problem. I’ve tried different header starts, and it still shows the exact same starter plot. I have also restarted the kernel and re-ran the script, and it still plotted the same plot as if there was no header indicated. It should be showing a plot from an interval of 56000 – 59000, and instead it is showing the entire plot from 51910 to 59000.