Genus 2 curve 8649.b.700569.1

• Label: 8649.b.700569.1
• Conductor: $8649$
• Discriminant: $700569$
• Mordell-Weil group: \(\Z/{2}\Z \oplus \Z/{2}\Z\)
• Sato-Tate group: $E_6$
• \(\End(J_{\overline{\Q}}) \otimes \R\): \(\mathrm{M}_2(\R)\)
• \(\End(J_{\overline{\Q}}) \otimes \Q\): \(\mathrm{M}_2(\Q)\)
• \(\End(J) \otimes \Q\): \(\mathsf{CM}\)
• \(\overline{\Q}\)-simple: no
• \(\mathrm{GL}_2\)-type: yes

Minimal equation

$y^2 + (x^2 + x)y = 9x^5 + 2x^4 - 21x^3 - 22x^2 - 8x - 1$

(, )

Invariants

Conductor:	\( N \)	\(=\)	\(8649\)	\(=\)	\( 3^{2} \cdot 31^{2} \)
Discriminant:	\( \Delta \)	\(=\)	\(700569\)	\(=\)	\( 3^{6} \cdot 31^{2} \)

Igusa-Clebsch invariants

\( I_2 \)	\(=\)	\(1132\)	\(=\)	\( 2^{2} \cdot 283 \)
\( I_4 \)	\(=\)	\(73377\)	\(=\)	\( 3^{2} \cdot 31 \cdot 263 \)
\( I_6 \)	\(=\)	\(21088959\)	\(=\)	\( 3 \cdot 17 \cdot 31 \cdot 13339 \)
\( I_{10} \)	\(=\)	\(369024\)	\(=\)	\( 2^{7} \cdot 3 \cdot 31^{2} \)

Automorphism group

\(\mathrm{Aut}(X)\)	\(\simeq\)	$C_6$
\(\mathrm{Aut}(X_{\overline{\Q}})\)	\(\simeq\)	$D_6$

Rational points

All points: \((1 : 0 : 0),\, (-1 : 3 : 3),\, (-2 : 3 : 3)\)

Number of rational Weierstrass points: \(3\)

This curve is locally solvable everywhere.

Mordell-Weil group of the Jacobian

Group structure: \(\Z/{2}\Z \oplus \Z/{2}\Z\)

Generator	$D_0$						Height	Order
\((-2 : 3 : 3) + (-1 : 3 : 3) - 2 \cdot(1 : 0 : 0)\)	\((3x + z) (3x + 2z)\)	\(=\)	\(0,\)	\(9y\)	\(=\)	\(z^3\)	\(0\)	\(2\)
\((-1 : 3 : 3) - (1 : 0 : 0)\)	\(3x + z\)	\(=\)	\(0,\)	\(9y\)	\(=\)	\(z^3\)	\(0\)	\(2\)

2-torsion field: 3.3.961.1

BSD invariants

Hasse-Weil conjecture:	verified
Analytic rank:	\(0\)
Mordell-Weil rank:	\(0\)
2-Selmer rank:	\(2\)
Regulator:	\( 1 \)
Real period:	\( 5.541099 \)
Tamagawa product:	\( 4 \)
Torsion order:	\( 4 \)
Leading coefficient:	\( 1.385274 \)
Analytic order of Ш:	\( 1 \)   (rounded)
Order of Ш:	square

Local invariants

Prime	ord(\(N\))	ord(\(\Delta\))	Tamagawa	L-factor	Cluster picture
\(3\)	\(2\)	\(6\)	\(4\)	\(1 - 3 T + 3 T^{2}\)
\(31\)	\(2\)	\(2\)	\(1\)	\(1 - 4 T + 31 T^{2}\)

Galois representations

For primes $\ell \ge 5$ the Galois representation data has not been computed for this curve since it is not generic.

For primes $\ell \le 3$, the image of the mod-$\ell$ Galois representation is listed in the table below, whenever it is not all of $\GSp(4,\F_\ell)$.

Prime \(\ell\)	mod-\(\ell\) image	Is torsion prime?
\(2\)	2.240.1	yes
\(3\)	3.480.12	no

Sato-Tate group

\(\mathrm{ST}\)	\(\simeq\)	$E_6$
\(\mathrm{ST}^0\)	\(\simeq\)	\(\mathrm{SU}(2)\)

Decomposition of the Jacobian

Splits over the number field \(\Q (b) \simeq \) 6.6.772987077.1 with defining polynomial:
  \(x^{6} - x^{5} - 28 x^{4} + 51 x^{3} + 75 x^{2} - 98 x - 92\)

Decomposes up to isogeny as the square of the elliptic curve isogeny class:
  \(y^2 = x^3 - g_4 / 48 x - g_6 / 864\) with
  \(g_4 = -\frac{16934823333}{3104} b^{5} + \frac{15604267599}{1552} b^{4} + \frac{223933318713}{1552} b^{3} - \frac{1241168535621}{3104} b^{2} - \frac{111941475201}{1552} b + \frac{462072237363}{776}\)
  \(g_6 = -\frac{579872195059509}{6208} b^{5} + \frac{1068664047901587}{6208} b^{4} + \frac{15335612391671001}{6208} b^{3} - \frac{2656270916385201}{388} b^{2} - \frac{958200176670183}{776} b + \frac{7911131565422907}{776}\)
   Conductor norm: 1

Endomorphisms of the Jacobian

Of \(\GL_2\)-type over \(\Q\)

Endomorphism ring over \(\Q\):

\(\End (J_{})\)	\(\simeq\)	\(\Z [\frac{1 + \sqrt{-3}}{2}]\)
\(\End (J_{}) \otimes \Q \)	\(\simeq\)	\(\Q(\sqrt{-3}) \)
\(\End (J_{}) \otimes \R\)	\(\simeq\)	\(\C\)

Smallest field over which all endomorphisms are defined:
Galois number field \(K = \Q (a) \simeq \) 6.6.772987077.1 with defining polynomial \(x^{6} - x^{5} - 28 x^{4} + 51 x^{3} + 75 x^{2} - 98 x - 92\)

Not of \(\GL_2\)-type over \(\overline{\Q}\)

Endomorphism ring over \(\overline{\Q}\):

\(\End (J_{\overline{\Q}})\)	\(\simeq\)	an Eichler order of index \(3\) in a maximal order of \(\End (J_{\overline{\Q}}) \otimes \Q\)
\(\End (J_{\overline{\Q}}) \otimes \Q \)	\(\simeq\)	\(\mathrm{M}_2(\)\(\Q\)\()\)
\(\End (J_{\overline{\Q}}) \otimes \R\)	\(\simeq\)	\(\mathrm{M}_2 (\R)\)

Remainder of the endomorphism lattice by field

Over subfield \(F \simeq \) \(\Q(\sqrt{93}) \) with generator \(-\frac{1}{2} a^{4} + 13 a^{2} - \frac{23}{2} a - 23\) with minimal polynomial \(x^{2} - x - 23\):

\(\End (J_{F})\)	\(\simeq\)	\(\Z [\frac{1 + \sqrt{-3}}{2}]\)
\(\End (J_{F}) \otimes \Q \)	\(\simeq\)	\(\Q(\sqrt{-3}) \)
\(\End (J_{F}) \otimes \R\)	\(\simeq\)	\(\C\)

  Sato Tate group: $E_3$
  Of \(\GL_2\)-type, simple

Over subfield \(F \simeq \) 3.3.961.1 with generator \(-\frac{17}{97} a^{5} + \frac{1}{97} a^{4} + \frac{437}{97} a^{3} - \frac{450}{97} a^{2} - \frac{700}{97} a + \frac{60}{97}\) with minimal polynomial \(x^{3} - x^{2} - 10 x + 8\):

\(\End (J_{F})\)	\(\simeq\)	\(\Z [\frac{1 + \sqrt{-3}}{2}]\)
\(\End (J_{F}) \otimes \Q \)	\(\simeq\)	\(\Q(\sqrt{-3}) \)
\(\End (J_{F}) \otimes \R\)	\(\simeq\)	\(\C\)

  Sato Tate group: $E_2$
  Of \(\GL_2\)-type, simple