Genus 2 curve 1386.a.9702.1

• Label: 1386.a.9702.1
• Conductor: $1386$
• Discriminant: $9702$
• Mordell-Weil group: \(\Z/{2}\Z \oplus \Z/{2}\Z\)
• Sato-Tate group: $\mathrm{SU}(2)\times\mathrm{SU}(2)$
• \(\End(J_{\overline{\Q}}) \otimes \R\): \(\R \times \R\)
• \(\End(J_{\overline{\Q}}) \otimes \Q\): \(\Q \times \Q\)
• \(\End(J) \otimes \Q\): \(\Q \times \Q\)
• \(\overline{\Q}\)-simple: no
• \(\mathrm{GL}_2\)-type: yes

Minimal equation

$y^2 + (x^2 + x)y = x^5 + 20x^4 + 104x^3 + 20x^2 + x$

(, )

Invariants

Conductor:	\( N \)	\(=\)	\(1386\)	\(=\)	\( 2 \cdot 3^{2} \cdot 7 \cdot 11 \)
Discriminant:	\( \Delta \)	\(=\)	\(9702\)	\(=\)	\( 2 \cdot 3^{2} \cdot 7^{2} \cdot 11 \)

Igusa-Clebsch invariants

\( I_2 \)	\(=\)	\(472004\)	\(=\)	\( 2^{2} \cdot 13 \cdot 29 \cdot 313 \)
\( I_4 \)	\(=\)	\(2486881\)	\(=\)	\( 37 \cdot 67213 \)
\( I_6 \)	\(=\)	\(389970923697\)	\(=\)	\( 3^{2} \cdot 97 \cdot 173 \cdot 2582093 \)
\( I_{10} \)	\(=\)	\(1241856\)	\(=\)	\( 2^{8} \cdot 3^{2} \cdot 7^{2} \cdot 11 \)

Automorphism group

\(\mathrm{Aut}(X)\)	\(\simeq\)	$C_2^2$
\(\mathrm{Aut}(X_{\overline{\Q}})\)	\(\simeq\)	$C_2^2$

Rational points

All points: \((1 : 0 : 0),\, (0 : 0 : 1)\)

Number of rational Weierstrass points: \(2\)

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
\(D_0 - 2 \cdot(1 : 0 : 0)\)	\(x^2 + 10xz + z^2\)	\(=\)	\(0,\)	\(2y\)	\(=\)	\(9xz^2 + z^3\)	\(0\)	\(2\)
\((0 : 0 : 1) - (1 : 0 : 0)\)	\(x\)	\(=\)	\(0,\)	\(y\)	\(=\)	\(0\)	\(0\)	\(2\)

2-torsion field: \(\Q(\sqrt{6}, \sqrt{22})\)

BSD invariants

Hasse-Weil conjecture:	verified
Analytic rank:	\(0\)
Mordell-Weil rank:	\(0\)
2-Selmer rank:	\(2\)
Regulator:	\( 1 \)
Real period:	\( 3.977728 \)
Tamagawa product:	\( 2 \)
Torsion order:	\( 4 \)
Leading coefficient:	\( 0.497216 \)
Analytic order of Ш:	\( 1 \)   (rounded)
Order of Ш:	square

Local invariants

Prime	ord(\(N\))	ord(\(\Delta\))	Tamagawa	L-factor	Cluster picture
\(2\)	\(1\)	\(1\)	\(1\)	\(( 1 - T )( 1 + T + 2 T^{2} )\)
\(3\)	\(2\)	\(2\)	\(1\)	\(( 1 - T )( 1 + T )\)
\(7\)	\(1\)	\(2\)	\(2\)	\(( 1 + T )( 1 + 4 T + 7 T^{2} )\)
\(11\)	\(1\)	\(1\)	\(1\)	\(( 1 + T )( 1 - 4 T + 11 T^{2} )\)

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?
\(2\)	2.180.3	yes
\(3\)	3.90.1	no

Sato-Tate group

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

Decomposition of the Jacobian

Splits over \(\Q\)

Decomposes up to isogeny as the product of the non-isogenous elliptic curve isogeny classes:
  Elliptic curve isogeny class 21.a
  Elliptic curve isogeny class 66.b

Endomorphisms of the Jacobian

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

Endomorphism ring over \(\Q\):

\(\End (J_{})\)	\(\simeq\)	an order of index \(2\) in \(\Z \times \Z\)
\(\End (J_{}) \otimes \Q \)	\(\simeq\)	\(\Q\) \(\times\) \(\Q\)
\(\End (J_{}) \otimes \R\)	\(\simeq\)	\(\R \times \R\)

All \(\overline{\Q}\)-endomorphisms of the Jacobian are defined over \(\Q\).